Would you ever have a sixual relationship with any of your cousins?
Albeit it'd have to be legal in your country/state/hometown.
Since the gene pool of cousins are different it's alright to do this and have kids since the pool isn't stale (like in brother/sister relations). Many people do it but rarely tell their families about it in case of dividing it. People preach tolerance and acceptance for other things (like homosixuality etc) but won't let go of the negative stigma attached to these relationships, course I'm strictly talking about cousin relations (legal), not siblings (illegal).