So, if you're 18 and able to express yourself legally, you can marry your sibling or first cousin, if that sibling or first cousin is also 18 and able to express him/herself legally? Really? How about a parent and his/her 18 year old child? Seems to me there are a few conditions that prevent these combinations and some others along the same lines. Gays can have their civil unions and all that implies. Fine. But redefining marriage goes too far. Sorry.