How Older Brothers Influence Homosexuality

Here’s what we know: Homosexuality is normal. Between 2 and 11 percent of human adults report experiencing some homosexual feelings, though the figure varies widely depending on the survey.

Homosexuality exists across cultures and even throughout the animal kingdom, as the authors of a mammoth new review paper on homosexuality write. Between 6 and 10 percent of rams prefer to mount other rams, not ewes. Certain groups of female Japanese monkeys prefer the company of other females:

In certain populations, female Japanese macaques will sometimes choose other females as sexual partners despite the presence of sexually motivated male mates. Female Japanese macaques will even compete intersexually with males for exclusive access to female sexual partners.

Here’s what we don’t know: What, specifically, causes someone to become gay, straight, or something in between. Part of the explanation is genetic, but since most identical twins of gay people are straight, heredity doesn’t explain everything.

The “why” question is important because “there is a strong correlation between beliefs about the origins of sexual orientation and tolerance of non-heterosexuality,” according to the report authors, who hail from seven universities spanning the globe. Specifically, people who believe sexual orientation is biological are more likely to favor equal rights for sexual minorities. (When Atlantic contributor Chandler Burr proposed in his 1996 book, A Separate Creation, that people are born gay, Southern Baptists called to boycott Disney films and parks in protest against the publisher, Disney subsidiary Hyperion.) It shouldn’t matter whether people “choose” to be gay, but politically, it does—at least for now.

One of the most consistent environmental explanations for homosexuality is called the fraternal birth order effect. Essentially, the more older brothers a man has, the more likely he is to be gay. The effect doesn’t hold for older or younger sisters or younger brothers, or even for adoptive or step-brothers.

According to Ray Blanchard, a professor of psychiatry at the University of Toronto, the reason could be that the mother’s body mounts an immune attack on the fetus of her unborn son. As the report authors explain:

Male fetuses carry male-specific proteins on their Y chromosome, called H-Y antigens. Blanchard hypothesized that some of these antigens promote the development of heterosexual orientation in males … Because these H-Y antigens are not present in the mother’s body, they trigger the production of maternal antibodies. These antibodies bind to the H-Y antigens and prevent them from functioning.

With the H-Y antigens not functioning, it could be that the “be straight” signal in the fetus’s brain never flicks on.

Blanchard believes this phenomenon grows stronger with each boy a woman bears. Studies have found that a man without older brothers has about a 2 percent chance of being gay, but one with four older brothers has a 6 percent chance. (Meanwhile, other studies have found the relationship to be weak or nonexistent.) As psychologist Ritch Savin-Williams writes in an accompanying commentary, the outcome for any given baby boy might depend on the timing of the immune response and the fetus’s susceptibility to the antibodies.

Average prevalence in 2013 (Savin-Williams and Vrangalova)

According to the report, Blanchard now plans to test mothers of gay and straight men for the presence of these antibodies. If proven out, fetal birth order could do a lot to fill in the missing explanations for homosexuality. But there will still be remaining gaps, like why some firstborn sons are gay, why some identical twins of gay sons are straight, and why women are gay, to name just a few.

The review paper authors do rule out one explanation for homosexuality, however: That tolerance for gay people encourages more people to become gay.

“Homosexual orientation does not increase in frequency with social tolerance, although its expression (in behavior and in open identification) may do so,” they write.

That reasoning—that a tolerant society somehow encourages homosexuality to flourish—has been used to support anti-gay legislation in Uganda, Russia, and elsewhere. These laws do marginalize and shame gay people, the authors write. But they won’t do away with a sexual orientation that’s ubiquitous, enduring, and—whether through genes, or hormones, or antibodies—perfectly natural.

Equality Takes Work

Back in December, journalists were surprised when President Obama called exclusively on female reporters during a press conference. The president is not the only one explicitly focusing on getting women to have more of a say. Google’s technical employees recently found this message in their inbox: “I wanted to update everyone on our efforts to encourage women to self-nominate for promotion… We know that small biases—about ourselves and others—add up over time and overcoming them takes a conscious effort.” What is this about? Can women not speak up for themselves?

The answer is complicated. Much research suggests that women who “lean in” too much are likely to experience backlash. The Yale social psychologist Victoria Brescoll, for example, found that when a group of professional men and women was asked to evaluate the competence of male and female chief executives, they appraised “speaking up” differently depending on the gender of the speaker. Male executives were rewarded with higher ratings for speaking up while their female counterparts were punished for such assertiveness and received lower competence ratings than their quieter peers. Women do not prefer saying less: They anticipate the treatment they will receive when they say more.

field experiment, they observed that women were more likely to respond to a job advertisement for an administrative assistant position when the ad made it clear that wages were negotiable. In contrast, men preferred the ambiguous version of the ad, which did not indicate whether salary was negotiable. And it did not hurt them: Men were substantially more likely than women to negotiate their pay in jobs that left the negotiation of the wage ambiguous.

Removing uncertainty from situations like this can help women’s compensation catch up to men’s. In a survey of recent MBA-graduates, my colleagues Hannah Riley Bowles, Linda Babcock, and Kathleen McGinn found that in fields with high degrees of ambiguity around salary negotiation, the gender gap in initial salaries reached almost $10,000 per year, favoring men, even when controlling for a wide range of other salary predictors such as job function, pre-MBA work experience, job market activity, geographic location and job preferences. In contrast, in low-ambiguity fields, no significant gender pay gap was observable.

Transparency around the acceptability of negotiations is just one sort of transparency. Bringing transparency to other aspects of professional life would also help. For example, transparency has helped increase the fraction of women on corporate boards of the United Kingdom’s FTSE100 companies, from 12.5 percent in 2011 to more than 25 percent at the beginning of 2016. Today, there are no companies with all-male boards left among the FTSE100, a first in the history of the London Stock Exchange. Tracking numbers, setting goals and showing the progress, or lack thereof, helped move the needle without having to use quotas.

The use of big data in human resource management, often referred to as “people analytics,” is another way that greater information can bring about more fairness, as it enables companies to track biases much more precisely. Relying on data, MIT was one of the first universities to discover gender differences in space, resources, awards and salary. The data told the tale of what later was coined “performance-support bias” where female faculty did not receive the same kind of “support” as their male counterparts. Data being a “very MIT thing,” as the dean of the School of Science remarked, allowed the university to point to what was broken and made it easier to fix.

The Harvard Kennedy School, where I work, has similarly developed an elaborate measurement system to make the invisible visible and compensate accordingly. Too often, the provision of public goods that makes everyone better off goes unnoticed. Someone has to organize the speaker series, go the extra mile and support our students in their job searches, or serve on search and promotion committees. These services for the community matter—not just in academia but in pretty much any organization. Most partners in law or consulting firms would rather have someone else mentor their summer associates, even if everyone benefits from great future colleagues. It turns out that women are more likely to provide such services.

A clever experiment by Lise Vesterlund, Linda Babcock, Maria Recalde, and Laurie Weingart brought this to the forefront. Motivated by their own experiences as female faculty members, they wanted to explore whether women had a harder time saying “no” when asked for a favor, or what they referred to as “nonpromotable tasks.” They designed an experiment to find out why some people do the tasks everybody benefits from, but bring little to no credit to the people who actually do the work.  It turns out, in groups made up of either men or women only, men and women both stepped up at about the same rate. But in groups made up of both men and women, the pattern changed. Women stepped up far more often. Nobody was surprised by this. It conformed to both men’s and women’s expectations of what the right thing to do was. Belonging to a social category expected to be more “caring” had turned into a liability for women.

By measuring and compensating accordingly, organizations can bring such inequities out into the open and assign value to tasks that are important to them. As the saying goes: What does not get measured, does not count. As a design, this is almost a pure win-win. True, not everything is quantifiable, which is why every few years the HKS faculty has a discussion about whether our workload system measures and rewards effort adequately at the Kennedy School.

Nobody is immune from self-stereotyping. Seeing is believing, and as long as people see more women in care-giving and more men in bread-winning roles, they are more likely to associate care with women and work with men. And of course, women’s reluctance to speak up can also turn into a self-fulfilling prophecy where people associate “speaking” with men and “listening” with women. To break the vicious cycle, those in power need to design systems that promote fairness—by calling on women, increasing transparency, and measuring and compensating all contributions. It works.

Work in the Only Industrialized Country Without Paid Maternity Leave

Tara is a working mother of two, with a son just shy of two and a daughter, Baby C, born in late January 2016. I met Tara on Facebook when she contacted me after watching my TED talk on parental leave in the United States. She is one of the many American parents who have no access to parental leave, paid or unpaid. Tara’s time off with her new baby consisted of her 13 days of accumulated vacation time; she was back at work 20 days after giving birth.

Part One: Life in the Only Industrialized Country Without Paid Maternity Leave


The first half of this two-part series followed Tara and her family through the birth of Baby C and her 20 days off work. Here, we rejoin Tara on her first day back on the job. (Tara has asked that I not use her last name in order to protect her privacy and her job.)

Tara is a manager at a small business—small enough that Tara is ineligible for the Family Medical Leave Act’s unpaid leave provision. She is her family’s sole breadwinner. A painful chronic condition has left her husband unable to work, and he is the primary caregiver for the children. Tara’s commute is 90 minutes each way, but her employer has agreed to let her work from home for a while—exactly how long has been left undetermined—after the birth of Baby C.



Within a few minutes of starting her first day, Tara emails me: “I’m on the phone getting a new password for work. Not even 8 A.M. and my poor little girl is crying inconsolably. Doesn’t want the bottle, wants the breast. My heart is being ripped out already!”

Tara’s husband is able to get Baby C settled down with a bottle of expressed breast milk, but her first day proves to be a long and busy one.



At three weeks old, a baby can nurse as frequently as every hour throughout the day and night. Tara fits in nursing Baby C when she can during the workday. She knows from experience with her first baby that once she is back at the office, she will have difficulty finding the time to pump.



Tara also feels lucky to be able to work from home for now.



But working from home, with a nursing baby, does have some occupational hazards.



Luckily, Baby C missed the laptop.

Tara’s job entails a lot of time on the phone and on Internet chat with clients around the country. When her husband has to step out one day (I later learned that this “errand” was to attend a funeral), things get chaotic.



Tara finds that some of her clients are stunned when they realize she is back at work when her baby is so young.



California is one of three states in the U.S. (along with Rhode Island and New Jersey) that have implemented paid-family-leave laws. A national-level program called The FAMILY Act has also been proposed by Kirsten Gillibrand, a Democratic senator from New York.

The existing state programs vary in the details, but they follow a basic insurance model: Employees (and in New Jersey, employers as well) pay regularly into a fund built onto the state’s temporary disability-insurance program. When workers take leave for births, adoptions, sick relatives, or their own illnesses, they are paid out at a percentage of their typical income.

Implemented in 2004, California’s program, called the Paid Family Leave Act (PFL), is the oldest of these programs. It is funded by employee contributions, and provides 55 percent of wage replacement for up to six weeks. 1.7 million California PFL claims were filed from 2004 to March 2015; the vast majority of these claims were made by new parents.

I ask Tara if her family could afford a leave in which only 55 percent of her income were replaced.



Prior to the passage of PFL, the California Chamber of Commerce put the bill at the top of its list of “job killer” legislation and convened other business groups to oppose the bill. The group warned of the “cost and burden for all California employers, especially small employers.” A spokesperson for the CalChamber estimated that the law would cost California employers $2.5 billion a year.

So far, these predictions have not materialized. A 2011 study looked at the business impacts of the first six years of the California PFL program. About 90 percent of firms surveyed reported that the law had neutral or positive effect on “productivity, profit, morale, and costs.” The study noted the “surprising” finding that “small firms reported even fewer problems than large firms.” The California study also found that use of PFL had “a positive effect on [workers’] ability to arrange child care” and that it “doubled the median duration of breastfeeding for all new mothers who used it.”

A smaller study was conducted on the first two years of New Jersey’s paid-family-leave program where, unlike California, employers also make regular financial contributions. The New Jersey study found that a majority of businesses, including small businesses, “have experienced no effects on business profitability/performance and employee productivity.”

Proposed programs in Connecticut and Washington D.C., and a recently passed plan in New York state that will begin in 2018, go further than the three existing state-level paid-leave programs. (Washington state has also passed a policy but not implemented it and has no deadline to do so.) These proposals add job protection, a benefit currently offered only in the Rhode Island program. New York’s plan is funded by employee contributions and provides 12 weeks of leave. It will be phased in starting in January 2018, with wage replacement eventually rising to 67 percent. (The total amount paid to workers will be capped at two-thirds of New York state’s average weekly wage.) The proposal in Washington D.C. would provide 16 weeks of paid family leave and would rely solely on employer contributions. It would also utilize a “progressive paycheck-replacement calculation” so that low-income workers would receive close to 100 percent of their wages.

To hear the perspective of a small business owner, I spoke with Emily Strittmatter, the chief operating officer and part-owner of Fort Worth Urgent Care Management in Fort Worth, Texas.

Strittmatter’s business employs about 30 people. When an employee is expecting a baby, Strittmatter said, “we try to offer flexibility” in unpaid leave, but that it is “not financially possible” for the company to pay employees during family leave. She explained, “It would cost us at least $10,000 for a full-time employee to take 12 weeks [of leave]. The reality for a small business is that it would be very, very hard to do it based on the profit margin.”

But Strittmatter stressed, “It’s something we’d love to do. We believe that treating your employees with respect is the best way to run a great business. And (being able to offer paid leave) would help us competitively. … We’re fighting for the same talent as big corporations, but with a lot less money to do it.”

That competition factor was echoed by Michelle Sternthal, the deputy director of policy and government affairs for The Main Street Alliance, an advocacy group for issues affecting small businesses. A 2015 Main Street Alliance survey of 1,163 small business owners found that only 13 percent offer any paid family leave, but 64 percent would support “a paid-family-leave policy that applies nationwide.” Sternthal argued that in terms of recruitment, paid family leave for small businesses would “level the playing field” with bigger companies.

Strittmatter expressed optimism about the existing and proposed state-level paid-leave programs: “That is so much more feasible than us trying to pay an employee’s leave ourselves. … I can’t imagine why any small business owner would be opposed to this if they understood how it works.”

I also spoke with David Karabinos, the CEO of health-care-technology company PointClear Solutions, which employs about 75 people in Georgia, Tennessee, Alabama, and New York. Karabinos said that his wariness about paid leave is purely financial: “If a small business gets in a cash-flow crunch because its customers aren’t paying on time, and it also has people out on maternity leave—even if it’s only four or five ladies in a company of 100 people—that’s huge.”

But when I briefly described the existing and proposed state-level family-leave insurance programs, Karabinos was somewhat more bullish. He said that “for those of us who don’t like taxes, the employer would not be in favor of [employer contributions].” But, he said, “The kinds of state plans that you’re talking about … if it costs the company a tiny amount of money per pay period, I think the company should consider doing it. For us to be successful, we have to attract smart, talented people … If this plan that we’re talking about could be leveraged for multiple family reasons, I think that’s an even better pitch.”

Some small businesses are not waiting for state or federal paid-family-leave programs to arrive. In 2014, Franz Spielvogel implemented 120 days of paid parental leave for all employees who work at least 24 hours per week at one of his restaurants—more than a dozen Laughing Planet Café locations in Oregon and Nevada. He told me that his program is working, even at an average cost of $15,000 for every employee who takes the full leave. “I have super loyal employees who are happy to come back to work,” he said. “More importantly, we haven’t had sick babies. [When a baby goes into daycare very early] you lose that employee a lot more because they have a child who gets sick a lot. We have lower retraining and rehiring costs, and it’s also proven to be a recruitment tool. Not just for women—people want to work with a company where the mission and values are aligned with their values. I wondered if this would be something I’d have to change a year from now, but I see it as a great investment.”

Still, in 2015, National Federation of Independent Businesses (NFIB) President Jack Mozloom said that the federation’s members “are strongly opposed” to a paid-leave mandate, and the Society for Human Resource Management (SHRM), a membership organization for individual HR professionals, has taken a public position supporting only voluntarily provided paid-leave programs. NFIB did not respond to requests for comment on this story, but I spoke with Lisa Horn, SHRM’s Director of Congressional Affairs. Horn said that voluntary paid family leave is the better option because it allows employers, who “are closer to their employees than the government is,” to create programs that work for them. And, she said, as companies compete for talent, paid leave is part of an “HR recruitment and retention strategy.” But under this voluntary status quo, according to the U.S. Bureau of Labor Statistics, only 12 percent of working parents are offered paid leave by their employers.

Horn also expressed SHRM’s concerns about the long-term solvency of paid-family-leave insurance programs, saying, “The FAMILY Act is a tax on both employers and employees—although I’ll admit that the tax is pretty minimal. Just like with Social Security, you have solvency questions. If you have a large number of employees calling on this program, that tax will have to go up.”

But Ellen Bravo, the executive director of Family Values @ Work, a network of coalitions working for family-friendly workplaces, disagrees. “Five states have had temporary-disability-insurance plans … since the 1940s. None of them has ever had a problem with solvency,” she told me. “In the three states with paid family leave, rates have not gone up. [SHRM’s stance] is the same prediction of doom we hear from opponents on every new workplace standard, from minimal fire safety to ending child labor and instituting unpaid FMLA. It has no basis in fact.”

Support for paid family leave is not coming from only the more liberal-leaning areas of the political world. The American Enterprise Institute, a conservative think tank, released a statement this month highlighting the failure of FMLA to cover 40 percent of workers, noting that voluntary corporate paid leave often leaves out low-wage workers, and underscoring the importance of participation of women in the economy. The group noted that paid leave helps more women to return to the workforce after giving birth, saying that “not only do household earnings rise when women go back to work following leave; the overall economy benefits as well.”

Back at her home office, Tara is wrapping up another work week and starting to worry about her return to the office. She is anxious about being a 90-minute drive away, should anything happen to her husband, who is in charge of “two kids, three pets, and a chronic disease.”

But Tara also speaks often of her deep pride in her job. She loves her work, and she’s proud to contribute to the family as breadwinner. In her early postpartum exhaustion, she doesn’t like when she can’t perform to her own high standards.



Three weeks after her return to work, Tara has to go into the office for the first time, for a management meeting.



She brings her breast pump along.




Tara says that her manager and co-workers were surprised that she came back to work so quickly. I ask Tara if they understand that she simply can’t afford unpaid leave. She says, “I think people assume I’m just crazy and wanted to work that soon, or more likely fail to consider that we have bills to pay and not much in savings.”

A few days later, Tara texts me about a post she saw on a Facebook parents’ group she belongs to.



It turns out that this is mostly true: In order to support the animals’ socialization, bonding, and nutrition, half of U.S. states have laws stipulating that a puppy or kitten cannot be removed from its mother to be sold until it is between six and eight weeks of age. Baby C, a human, is nearing eight weeks of age now, and her mother has been back at work for a month.

For two months, I have been witness—by text—to Baby C’s entry into the world, Tara’s time at home with her, and Tara’s return to work. As we wrap up our text communications, I ask Tara whether it bothers her to see advances in paid leave come too late for her and her family.



In the end, Tara is focused on the dual jobs of work and motherhood. “I have to do what I have to do to pay the mortgage and keep food on the table,” she says. “I think we are an average American family, working to pay our debts and pave our own way.”

But still, she writes, “I really hope my kids get more time off to bond with their babies.”


This piece is the second in a two-part series about one woman’s maternity leave and her return to work. The first part is here.