Читать книгу The Complete Parenting Collection - Steve Biddulph, Steve Biddulph - Страница 36

In Janine’s baby’s tiny body, at around the eighth week of pregnancy, the Y chromosomes stir in the cells and testosterone starts being made. As a result of this new chemical presence, the baby starts to become more of a boy, growing testicles and a penis, and making other more subtle changes in his brain and body. Once the testicles are formed (by the fifteenth week they are fully developed), they start to make testosterone, too, so he becomes progressively more and more masculine.

If Janine is very stressed, her body may suppress the testosterone in baby Jamie’s body, and he may not fully develop his penis and testicles, so he will be incompletely developed at birth. He will catch up, however, in the first year.

Right after birth, young Jamie will have as much testosterone in his bloodstream as a twelve-year-old boy! He has needed all this testosterone to stimulate his body to develop male qualities in time to be born. This ‘testosterone hangover’ will result in him having little erections from time to time as a newborn.

By three months of age, the testosterone level will drop off to about a fifth of the birth level, and throughout toddlerhood the level will stay pretty low. Boy and girl toddlers (I’m sure you’d agree) behave pretty much the same.

At the age of four, for reasons nobody quite understands, boys receive a sudden surge of testosterone, doubling their previous levels. At this age, little Jamie may become much more interested in action, heroics, adventures and vigorous play. His dad may well find that this age is a good one because Jamie can now play ball games, and they can do gardening together: they can interact in ways that were not possible when he was little and helpless.

At five years of age, the testosterone level drops by a half, and young Jamie calms down again, just in time for school! Enough testosterone is still around for him to be interested in activity, adventure and exploration, but not especially interested in girls.

Somewhere between the ages of eleven and thirteen, the level start to rise sharply again. Eventually – usually around fourteen – it will increase by some 800 percent over the level of toddlerhood. The result is a sudden growth and elongation of his arms and legs – so much so that his whole nervous system has to rewire itself. In about 50 percent of boys, the testosterone levels are so high that some of it converts into estrogen, and breast swelling and tenderness may be experienced. This is nothing to worry about.