Part I. Sugar and Spice vs. Snips and Snails: Do Baby Girls Develop More Quickly than Boys?

Part I in a series exploring gender differences in child development

It happens everyday in your neighborhood playground: a friendly question posed by one parent to another (My, she’s a good walker. How old is she?) quickly leads to unsolicited reassurances: Oh, well he is a boy. They take longer to start walking. Or My daughter was an early talker, too. I’m so glad I have a girl.

You’d think little boys are Cro Magnons to little girls’ upright humans. Are these casually-repeated beliefs about boys and girls even based on the facts?

Here at Circle of Moms, we have access to a tremendous amount of mom-reported data: moms have filled out the milestones their children attained, along with their children’s ages at the time, for over 300,000 children.  And if you believe the general stream of playground lore (that boys lag behind girls in most of their critical early milestones) the actual data might surprise you.

Walking and Smiling are Equal Opportunity Milestones

It turns out that while there are some notable differences, boys and girls reach many of their key early developmental milestones at roughly the same times. This latter category includes all the major gross motor skill milestones associated with making progress towards ambulation: rolling over, sitting up, crawling, pull-up-to-stand, and first steps, a cycle that’s usually complete for kids of both genders just after their first birthdays.

Boys and girls are also tied in one of the critical social graces generally thought to belong to girls: smiling.

Girls Lead in Words, Claps, and Sleep

So where do they differ?

Girls consistently hit speech milestones earlier than their brothers. The average time to utter a first intelligible word is during a baby’s seventh month. But girls reach the milestone a full three days earlier than boys (220 days vs. 223 days) and are 5% more likely to have spoken a word even before reaching seven months of age (36.6% vs 34.7%).

Girls also outperform boys at clapping, hands down. On average, they first put their palms together at 267 days; boys trail behind nine days.  And girls are 16% more likely to be clapping by the age of 9 months (58.8% vs 50.7%).

Parents of girls can also feel justified in believing that they have better sleepers. The average time to begin to sleep a decent stretch without waking up is during the third month of life. Girls begin to do this, on average, at 67 days, while boys keep their parents on their feet an additional 5 days. And girls are 17% more likely to have slept through the night by 2 months (48.4% vs. 41.5%).

A Mouthful of Bragging Rights for Boys

Boys are no slackers though, and they seems to outpace girls in most areas related to the development of their mouths. They may be slow to say a word that their parents can understand, but they start trying earlier. Our data show that they begin to babble on average three days earlier than girls (101 days vs. 104 days). And they get their first several teeth earlier as well: 60% of boys reach this milestone by the age of 7 months (compared to only 55% of girls) and 62% have their third tooth by 9 months (compared to only 52% of girls).

Finally, boys start laughing an average of five days earlier than girls, at 83 days. And they are 20% more likely (26.7% vs 22.4%) to share a giggle with their caretakers by the tender age of two months.

Which means girls have the last laugh after all.

Did your kids follow these patterns? How do you account for the differences?

Next week we will continue to explore gender differences throughout child development, examining boys and girls between the ages of 1 and 5.