And indeed, in canvassing dozens of mothers, I found that many of their feelings about the challenges of raising each sex echo Baron-Cohen's conclusions. Here are some of the things mothers said about their daughters.
Girls are emotionally high maintenance.
Many mothers noted that girls, even as babies, are more volatile than boys, who seem more apt to go with the flow. "My 5-year-old daughter can go from smiles to tears and back again in the time it takes to eat dinner," says Lisa Young, a Chicago mother of two. "Every meal is high drama. Her 10-year-old brother, on the other hand, has never been interested in doing anything more than wolfing down his food and getting back to whatever he was doing."
Moreover, Melissa Ferry, from Valparaiso, Indiana, believes the transformation from happy child to sullen adolescent is more abrupt with girls. "They seem to morph overnight from sweet, adorable, loving daughters to impossible teenagers," says this mother of two girls, 14 and 1, and a boy, 9. "From what I've observed, boys give you a bit more warning."
Girls talk back more.
Scientists have known for some time that the left side of the brain controls language. In the late 1980s, behavioral neurologist Norman Geschwind, MD, speculated that the more fetal testosterone there is, the faster the right side of the brain develops and the slower the left. This may account for the fact that baby girls -- who also have the hormone testosterone but generally in far lower concentrations than boys -- often speak earlier than baby boys and why, in infancy, girls show more activity in their left brain hemispheres than in their right when listening to speech. The good news is that "girls are more verbal, so you know what they are thinking," says Jessica Finkbiner, a mother of a daughter, 5, and two sons, 2 and 4 months, from Northridge, California. The downside? "You have to deal with a lot more sass."
Girls' bullying can be emotionally harsher.
In Baron-Cohen's research, both genders exhibit aggression, but in boys it tends to take a more conventional form (physical fighting), whereas in girls, it is usually more subtle, manifesting itself in gossip, social exclusion, and verbal meanness (such as cutting remarks, often made behind the victim's back).
Perhaps girls are adept at this kind of bullying because they are more tuned in to the emotional lives of other people, and hence understand intuitively the impact -- which, according to most moms, is more brutal than a simple blow. "I've dealt with property damage and a few broken bones while raising my three sons," says Ann Douglas, the author of The Mother of All Parenting Books (John Wiley, 2002), whose four children range in age from 6 to 15, "but those things were a breeze compared to the odd-girl-out bullying my daughter endured as a preteen." What's more, Douglas says, the aftereffects of a verbal snipe linger far longer than those of a physical bruise.