Boys vs girl have sex

Curious about some stereotypical behavior you've noticed in your little one, or wondering what to expect if you're expecting a son or daughter? It turns out that gender differences aren't that significant — though there are a few that start in the womb and continue through childhood. In terms of anatomy, differences between boys and girls can be pretty obvious. But when it comes to brain development, the disparities between the two sexes are actually pretty small.

Zyler, wearing rainbow leggings, scrutinized a pair of hot-pink-and-purple sneakers. Kadyn, in a T-Rex shirt, fixated on a musical cube that flashed colorful lights. Is Zyler a boy or a girl? How about Kadyn? The Cambridge, Mass. A Facebook community for these parents currently claims about members across the U.

Worldwide, there are boy babies born for every girl babies. This skewed ratio is partly due to sex-selective abortion and "gendercide," the killing of female infants, in countries such as China and India where males are more desired. But even discounting those factors, the completely natural male-to-female sex ratio still hovers around , meaning that women are inherently more likely to give birth to boys. Several factors influence whether a sperm containing a Y sex chromosome or one containing an X chromosome will be first to fertilize an egg, including parental ages, their environmental exposure, stress, the stage in the mother's ovulation cycle and even whether she has had children previously; all these forces combine to set the average sex ratio at fertilization at

Ultrasounds have a variety of purposes during pregnancy, but the use that often receives the most attention is its ability to reveal the sex of the baby. Some parents-to-be can't wait to find out whether they're having a boy or a girl, while others choose to put off knowing the sex until birth. Either way, a sonogram — the grainy, black-and-white image that results from an ultrasound scan — will be baby's earliest picture and a couple's first chance to see the developing fetus.