sudas: It may one day be possible to modify the genes of a sperm, egg, or embryo so that defects like cystic fibrosis are replaced by normal genes. The movie GATACA takes this idea to extreme, and says one's motivation may override gene predestination. Well, if you're going to do that for disease, followed perhaps by intelligence or physical characteristics, how about penis size and shape? Maybe you borrow penis genes from someone you know, or contributions from a gene-bank. Those who doubt there are 14-17" ones out there would be the first in line to buy. As you may know, we can even mix genes from different plants and animals. Perhaps you could give your son a dog's penis. Hung like a horse could mean that literally. First a big dick, then a big dickhead, then a dog's knot. While your at it, how about the partially-prehensile penis of a dolphin's? We're at the point in civilization that many defects, like near-sightedness, can be overcome by technology and are not selected against by evolution. Large penis genes could be selected for as men and women opt to encourage this in their offspring and by "artificial" social preference have it perpetuate itself through the gene pool.