Robert Heinlein:
"""Copulation is spiritual in essence--or it is merely friendly exercise. On second thought, strike out “merely.” Copulation is not “merely”--even when it is just a happy pastime for two strangers. But copulation at its spiritual best is so much more than physical coupling that it is different in kind as well as in degree.

The saddest feature of homosexuality is not that it is “wrong” or “sinful” or even that it can’t lead to progeny--but that it is more difficult to reach through it this spiritual union. Not impossible--but the cards are stacked against it.

But most sorrowfully--many people never achieve spiritual sharing even with the help of male-female advantage; they are condemned to wander through life alone.
"""