designer genes

Just read an article on genetic engineering by Michael Sandel from the Apr 2004 Atlantic. He opens the possibility of choosing genes in our kids for stronger muscles, better memories, tougher immune systems, etc. The major downside he focuses is the existential dilemma that such power creates. By having direct control over the genes of our children, will we love them less, take less appreciation in their talents? But we already do some degree of genetic engineering in selecting our spouses.

I think the more problematic issue is a reduction in genetic diversity in the species. Let's say there's a gene for tallness. So everyone wants it. Next generation, everyone has the "tall" gene. But let's say there's some kind of bad side effect to this gene. It could make our entire population vulnerable to disease or malformation. Species with genetic diversity are more resilient. But who should be forced to carry on the less-desirable genes? What is to prevent runaway sexual selection--the peacocks with tails too big to lift?

The power to select our own genes is also the power to evolve ourselves into extinction. I wonder what we will do once the technology becomes available.