Is it legal to marry my sister in the state of AZ. We have been talking about it and we plan on getting married.

It is illegal to marry your sister in Arizona.  A.R.S. § 25-101(A). That statute states, "Marriage between parents and children, including grandparents and grandchildren of every degree, between brothers and sisters of the one-half as well as the whole blood, and between uncles and nieces, aunts and nephews and between first cousins, is prohibited and void."