Two consenting adults, including relatives?

[Esquilax]

It's about marriage.

Yeah, I got that, but there was a pretty clear qualifier at the end of the quote you were responding to, that said consenting adults.

See, there are actually reasons why one wouldn't want children to marry, mainly due to the fact that they aren't fully equipped to give informed consent yet. Hell, there are some adults that find that hard; that's why we restrict what children can do, and educate them to prepare them for the future. At a certain point, when they become equipped to deal with some freedom, there's little we can do to stop them making poor sexual choices, but what we can do is educate them and give them means to stop those poor choices becoming permanent ones. Hence, most of us would not allow children to marry, but would allow them birth control.