Genetics and Your Baby

As you wait for baby, you've probably tried to picture what he might look like. Will he be tall like his father? Will he have curly hair like yours? Or is he going to inherit his grandfather's sense of humor?

Experts estimate that there are 60,000 to 100,000 genes (made up of DNA) in a human being's 46 chromosomes. A baby gets 23 chromosomes from his mother and 23 from his father. With all the possible gene combinations, one pair of parents has the potential to produce 64 trillion different children. This probably gives you an idea of how impossible it is to predict just what your baby will look like. The science of genetics is complicated, but with a short course you can get some information to guide your imagination.

Remember learning about genes and fruit flies in high school biology? Back then, you were told that the dominant gene always beats out the recessive one. Well, scientists have always known humans are more complicated than fruit flies. But in recent years, they've learned just how much more complicated.

As it turns out, most human traits are polygenic -- the result of many genes acting together. To complicate things even further, for some traits -- such as height, weight, and especially personality -- environment also has a significant influence on which genes are expressed and which remain muted.