It is not an indisputable interpretation of Scriptures, and it is hurtful to many, to conclude from Genesis 2:24 that God created marriage to exclude same-sex marriages. God is not the one who proclaims that passage, but Adam (or the writer of Genesis - all we know is that the verse immediately preceding the passage is specifically attributed to Adam). Genesis 2:24 does not in any way address same-sex couples as being proper or improper, and it does not explicitly state that God "created" marriage any more than God "created" other highly valued and much cherished sacraments, such as baptism or confirmation.
Incorrect Biblical interpretations can lead to serious error, as the reference to slavery in the New Testament led to the justification of slavery in America. In fact, clinging to a Gen. 2:24 interpretation as conclusively instructing Christians to oppose same-sex marriage is to err by not doing what God through Christ wants us to do - to follow Christ's calling - choosing to love one another and promote committed relationships between loving couples.