To the editor:

Teresa Gordon (Public Forum, April 5) misunderstands evolution. It isn’t something that happens to any individual; it happens to species. So species that manage to preserve themselves and reproduce have an evolutionary advantage. This is not precisely the same thing as individuals succeeding in preserving themselves and reproducing, and in the difference, you can find a sensible explanation for homosexuality.

It takes two people — one male, one female — to get their genes into the next generation. That’s the first step. Then, somehow, the next generation must survive long enough to get its genes into a succeeding generation. Humans do this by having comparatively few offspring but investing in them heavily. One way to optimize the investment is by having a stable and persistent rate of homosexuality. If I’m gay, then the way I get my genes into the next generation is by investing in my siblings’ children. Any population with a rate of homosexuality that optimizes the investment in the next generation has an evolutionary advantage.

So natural law does pertain to homosexuality. It prescribes it, though, rather than proscribing it.

Bradley Kemp,

Lawrence