I grew up in Los Angeles in the 1960s and ’70s as the middle of three sisters—no brothers—and I took the “boy role.” I was athletic, did more of the outside chores (although we all had to weed the lawn), and wore pants in elementary school as soon as school rules changed allowing us to do so.

I have a memory: After a winter break, my first grade teachers asked us to share our favorite holiday present. I said it was a desk from my grandmother (not really so thrilling), rather than the racecar set I had wanted and actually received, vaguely sensing it might be considered too boyish.

When I attended UC Berkeley at the end of the 1970s and early ’80s, sexism was as horrifying to us as, well, racism. I lived in a co-op, where women were disparaged for shaving their legs. (I did so anyway, but was slightly embarrassed.) Nature and nurture in gender differences wasn’t much of an issue at the time, but I certainly believed that a lot of “traditional” roles were driven by culture and society. When my older sister had a girl, I conscientiously bought her gender-neutral toys, which she never seemed interested in. It may not have helped that my sister and her husband happily embraced the princessy pink world for girls.

Then I married. And gave birth to a boy. And another. And like most parents who think of themselves as educated and liberal, we planned to raise our sons with as little gender stereotyping as possible. My husband and I both felt it was important that boys grow up free of the pressure of conforming to typical Western notions of masculinity, and that girls should feel they had every job opportunity possible in life. We agreed that stereotypes of either gender were damaging and limiting to the children themselves, as well as to society as a whole.

And we combined our last names, rather than give them just their father’s, into a new (unhyphenated) one for our children. That didn’t seem particularly radical then, but as time went on, it was clear some people felt it was.

So what happened? Was it the way we raised them, the way so­ci­ety mol­ded them, or in­nate bio­lo­gic­al and hor­mon­al dif­fer­ences between the sexes?

Later on, I thought nothing of buying a little pink stroller for my older son to push around London, where he was born. Or a play kitchen, which a friend, to my surprise, said her husband would never allow their son to have—it was too feminine.

Now at 19 and 16, the boys are very different from each other but have some of the same traits. They rarely share their feelings with me or, as far as I can tell, with their friends. They love watching and playing sports. Fantasy Football is nearly a religion.

So what happened? Was it the way we raised them, the way society molded them, or innate biological and hormonal differences between the sexes? Is it possible, or even desirable, to raise gender-neutral children? As to the first question, yes, yes, and yes. The second? That all depends on what is meant by gender-neutral.

First, let’s take a (very brief) overview of how gender differences have been perceived over time. Before the 1970s, it was generally believed that women were more able to express and share their emotions than men; women were more empathetic and nurturing. Those differences, however, were not usually valued, particularly in business and political arenas, where women were often labeled weak and irrational. In the 1970s and 1980s, some of this changed, particularly with the 1982 publication of In a Different Voice by Harvard Professor Carol Gilligan. Among other things, “feminine” characteristics were reframed in a positive manner—being caring and connected was better than the testosterone-driven aggression of men.

Gilligan’s writings had a powerful impact on gender studies by turning female “difference” on its head, from inferiority to superiority. But the point was still that men and women were vastly different. This idea was reinforced in the 1990s with books such as John Gray’s Men Are from Mars, Women Are from Venus—the two genders actually came from different planets!

Today, as the field of neuroscience has evolved, many researchers believe that the two sexes are far more similar than different. And the growth of the transgender movement has helped us realize that gender is more fluid and less fixed than many of us previously believed. “It’s time to move beyond the nature/nurture debate,” says Amanda Diekman, professor of psychology at Miami University in Ohio. “Yes, there are differences, but overall they are small to moderate in size. It doesn’t mean they’re not important, but we need to take them in the context of a lot of similarities.”

And it’s also time to dump that tired metaphor of Mars and Venus, believes Janet Hyde, Ph.D. ’72, professor of psychology and gender and women’s studies at the University of Wisconsin–Madison. A new metaphor to try on, she says, is less exciting but more realistic: Men are from North Dakota and women from South Dakota.

Of course, not everyone agrees—at least not wholeheartedly. “We don’t have the data to prove that there are only very slight differences between men and women, but it sounds reasonable,” said Alice Eagly, professor of psychology at Northwestern University, who has long worked in the area of gender differences. “I’m interested, however, in the very basic biological differences—men are bigger and taller, and women give birth. That can lead to tremendous behavioral differences.”

Louann Brizendine, who received her B.A. in neurobiology from Berkeley in 1976 and is a professor of clinical psychiatry at UCSF, is known—and often lambasted—for her emphasis on biology-driven differentiations between the genders.

In The Female Brain, for example, she writes that “girls arrive already wired as girls, and boys arrive already wired as boys. Their brains are different by the time they’re born, and their brains are what drive their impulses, values, and their very reality.” Girls, she believes, are more engaged with others from birth and have “an innate skill in observation … they arrive in the world better at reading faces and hearing emotional tones in human voices.” Boys, on the other hand, “driven by their testosterone-formed male brains, are compelled to investigate their environment,” even if they disobey a parent or teacher.

Brizendine now acknowledges that maybe “she let the pendulum swing too far the other way,” when writing about innate differences in the sexes. “Males and females are more alike than they’re different,” she says. “After all, we are the same species.”

In fact, significant research exists that debunks some long-held beliefs about gender-based disparities. Take one example: math and science ability. Not that long ago, in 2005, former Harvard University professor Lawrence Summers stated publicly that boys may have more innate ability in math and science than girls. It’s true that, historically, boys did better than girls on math and science tests, particularly in high school. But a 2008 analysis conducted by Janet Hyde’s team and Marcia Linn, professor of education at Cal, looked at data from SAT scores and 7 million state assessment tests of students from all grades. They found that there is no longer any difference between the two genders in math.

Some critics argue that while average performance might be equal, boys are better than girls at the highest level of mathematical ability, but Hyde and Linn said that this, too, didn’t prove to be true. And even though boys do score better than girls on the SAT math portion, Hyde and Linn say that may be because only college-bound seniors take the SAT, and more girls than boys take the test. Since more girls go to college, the test dips further down into the female talent pool. This last point shows just how easy it is to take one bit of information and draw gender conclusions, without examining the issue as a whole.

“Ac­tu­ally grow­ing a boy or a girl from those XY or XX chro­mo­somes re­quires con­stant in­ter­ac­tion with the en­vir­on­ment, which be­gins in the pren­at­al soup and con­tin­ues through all the dance re­cit­als, base­ball games, middle-school sci­ence classes, and cafet­er­ia dra­mas that cease­lessly re­in­force our gender-di­vided so­ci­ety.”

Lise Eliot, an associate neuroscience professor at Chicago Medical School, wrote Pink Brain, Blue Brain: How Small Differences Grow into Troublesome Gaps—and What We Can Do About It. She says, “Scientists no longer pit nature and nurture against each other as distinct, warring entities, but appreciate that they are intricately interwoven. Obviously boys and girls come into the world with a smattering of different genes and hormones. But actually growing a boy or a girl from those XY or XX chromosomes requires constant interaction with the environment, which begins in the prenatal soup and continues through all the dance recitals, baseball games, middle-school science classes, and cafeteria dramas that ceaselessly reinforce our gender-divided society.”

So, are there any innate differences that Eliot would point to between the sexes?

“Females outperform on verbal fluency—that is, how fast you can spit out words beginning with the same letter,” she said. “And boys are slightly better at mental rotation”—looking at something three-dimensional and imaging how it will look turned another way. The mental rotation is a type of spatial skill that can be influenced by prenatal testosterone, because girls exposed prenatally to more testosterone than is typical are also slightly better at spatial skills than girls who are not, she said.

Girls do still perform better on verbal portions of some standardized tests. But is that because they’re hardwired that way, or because they’re encouraged to read more than boys because reading might initially be easier? Or is it the case that it’s more acceptable to some parents to have a girl who is a bookworm, than it is to have a bookish boy?

“These are slight differences that grow into big differences based on what children do with their brains while growing up,” Eliot says. Gender stereotypes are very resilient and start at a very young age, and it’s difficult for even the most well-meaning parents to recognize when they are reinforcing them.

It’s not just a matter of avoiding pink for girls or embracing it for boys, or giving the same toys to boys and girls. Eliot points to experiments in which babies are dressed in gender-neutral clothes or purposely misidentified. People who thought the girls were boys called them angry or distressed more often than those who knew the babies were female. “Similarly, boys mislabeled as girls were more often seen as joyful or interested than they were when the sex was accurately revealed,” Eliot wrote.

Another 2000 study asked mothers of 11-month-old babies to estimate their child’s crawling performance down ramps and slopes. The mothers could adjust the ramps to the level at which they thought their baby would be comfortable. Mothers of girls underestimated their abilities; mothers of boys overestimated. In truth, boys and girls showed identical levels of motor skills.

I did want to raise my children with as little gender stereotyping as I could, but was this the same as raising gender-neutral kids? Is wanting a world where there is no gender discrimination the same as embracing pansexualism? I was not interested in—nor, to be honest, was I even aware of the option—of parenting like Marly Pierre-Louis, a blogger who wrote about the difficulties of raising her son without gender assumptions. She not only banned clothes displaying superheroes and words like “champ” and “all-star”; she also didn’t identify people to her son as being men or women. At two-and-a half, Pierre-Louis’s son “doesn’t categorize anything based on gender,” she wrote.

“My son doesn’t know he’s a ‘boy’; he doesn’t even know what that means, and he especially doesn’t understand it in opposition to a ‘girl,’” she went on. “As parents, we’re the ones who define these terms for our kids, and pick and choose what we put in their respective gender boxes. They can either accept it rigidly as ‘man’ and ‘woman’ or as fluid and flexible.”

I found this, if nothing else, complicated. (It might be politically correct, but is it grammatically correct to refer to a person as they?) Christia Spears Brown, however, an associate professor of psychology at the University of Kentucky, pointed out that we don’t need to abolish gender distinctions to be more aware of how often we use them.

“When adults always mention gender, kids think it must be very important,” said Brown, author of Parenting Beyond Pink & Blue: How to Raise Your Kids Free of Gender Stereotypes. “I use gender when relevant, but often I find a better word can be used.” In fact, she said, in one classroom study, half the teachers did the usual, seemingly innocuous gender labeling—“Good morning, boys and girls.” “Boys line up on the right, girls on the left.” The other half greeted their students with a general “good morning” and had them line up by, perhaps, hair or eye color. At the end of six weeks, those in the classrooms that used gender had stronger stereotypes of boys and girls than did the other classrooms, she said.

Many argue that boys and girls naturally divide when very young—boys race around the playground, while girls play in the housekeeping corner. But “naturally” is the key word here. “Imagine if on a playground, children played separately by race or religion,” Lise Eliot said. “The teachers would be embarrassed and make an effort to integrate the children.”

Brown said the aim of her book was not to wipe out differences between the sexes (her daughter wears pink dresses), but to show that many parents “are missing the mark in ways they’re not even aware of.” Children are bombarded all the time by toys, cartoons, television shows, and books that reinforce society’s beliefs about girls and boys, she said, “and if parents don’t correct those stereotypes head on, then kids hold a lot of beliefs that would surprise parents.”

For example, Brown said that when her daughter was six, she told Brown she needed to clean her room because “girls are clean and boys are messy.”

“I don’t even know where she got that from,” Brown recalled, but rather than laughing it off, she talked to her daughter about her assumptions. These don’t have to be long, heavy discussions—I remember a friend trying to explain the sociopolitical implications of Barbie dolls to her daughter, who wanted one. The girl listened to her mother’s lengthy explanation and then repeated her request for the toy.

So getting this right for Brown may mean correcting a child every time she repeats some silly thing she has heard. And parents should think more broadly about what they are trying to accomplish with their kids. Do you really care if your son has a doll, or are you trying to foster nurturing? If so, and the boy doesn’t like the doll, try a stuffed animal or a small pet.

The dress in which a son en­joys play­ing dress-up may get him un­wanted at­ten­tion at the preschool or kinder­garten.

Brown’s young daughter loves princess clothes, so her mother asked her what she liked about them. It turns out it was the pretty sparkling. So Brown offered as a substitute Wonder Woman clothes, which also sparkle, and her daughter was delighted.

Those kinds of options are often easier with girls, who have more freedom to act like boys than boys do adapting girl-like wardrobes and traits. The dress in which a son enjoys playing dress-up may get him unwanted attention at the preschool or kindergarten. The best thing is to give him a heads-up, Brown suggested, telling him he might get teased. “If it bothers you, we’ll take it off. If not, go ahead. I think it’s pretty unimportant.”

“You need to equip them to deal with stereotypes, but also the social realities of bucking stereotypes,” advises Brown.

Overcoming gender disparities may require us to take a more nuanced approach to problem solving. For example, if we want more girls and women, who are now woefully underrepresented, to take more science, technology, engineering, and math classes, and we agree that it’s not innate ability holding them back, the answer might be to show scientists, engineers, and mathematicians to be attractive and caring rather than nerdy. Or change the physical environment of classrooms and laboratories to make them more appealing to girls.

Then again, does this counter or reinforce gender stereotypes? Good people disagree.

One thing that’s easy to forget, as Janet Hyde points out, is that variations within genders are greater than variations between them. I see the truth of that in my own home. Both my boys are into sports, but one is far more talkative and intellectually curious, while the other ranks higher on intuition and emotional intelligence. If they were a boy and a girl, it would be easy to attribute these differences to gender. As it is, I guess I’ll have to blame—or credit—the vast and ever-shifting mishmash of biology, parenting, peer influence, and culture.

Alina Tugend writes the “ShortCuts” column for The New York Times. She received degrees in history and journalism from UC Berkeley. Follow her on Twitter at @atugend and see more of her work at www.alinatugend.com.