Its much easier to go along with the crowd

Sometimes social facts are social facts because its easier for everyone to just agree with everyone else. Example:

There is nothing wrong with being gay. But having a minority sexual preference by definition has costs: a lot fewer potential partners to choose from, for starters. It also makes having children with a partner much more complicated, at least until technology enables us to fuse the DNA from two eggs or two sperm. A loving, non-homophobic parent could choose to turn the gay genes off simply in order to ease their child’s life for reasons that have nothing to do with social stigma.

But of course, even aside from reinforcing (however implicitly) the idea that gayness is a problem, this [pills that make people not gay] is bad for other gay people. They suddenly have even fewer partners to choose from, even less political clout. Moreover, the more parents, or adults, who make that choice, the less attractive gayness becomes, which will tend to push marginal choosers into the “straight” camp. And the charge probably will be led by parents who make their children straight, not to avail them of the network benefits of a majority preference, but by parents who are simply repulsed by homosexuality. One imagines that the gay community will be somewhat resistant to letting those parents in effect make choices for them.

Moreover, reducing variance is bad genetic strategy. The less genetic variety you have, the more vulnerable you are to unforeseen circumstances; genetic variance is a reservoir of potential adaptations. Similarly, even if they were not worthwhile in themselves, the subcultures we now have the medical possibility of destroying are sources of dynamism in our society. We will all be poorer without them.

Actually, read the whole thing to get two other examples.