well, frankly, i don't think such broad studies are available. in that sense, this is an arguement awaiting the facts.
In the mean time, i think the best arguement is self-evident. While many relationships ultimately end in separation or divorce, there is no such thing as an ex-sibling. In subordinating the familial relation to the romantic one, there is a sharply increased risk of serious trauma to the family. The couple is imposing this risk on the other family members, as well. Would you like to choose between a brother and a sister in a messy divorce? Family members have duties to one other...to take up romantic relationship inevitably involves breach of those duties.
And no, i don't think the Bible condemns homosexual relationships. And no, i certainly don't think it "simply" says that women are to be subordinates. It names them as deacons, apostles, saints, disciples, judges, prophets, and elders. The more authentic we are to the words and teachings of Jesus...the vision we see is remarkably egalitarian.
http://www.whosoever.org/bible/
This link explains the various "slam" passages that are used against queers. Nor does each passage have equal weight, IMO. These isolated incidents conflict with greater message. Many authors and figures in the bible display a remarkable disregard for the sexual politics of their day: the adulteress woman, jesus' linage, tamar's conspiracy, etc... They ALWAYS display a remarkable concern for justice, love and responsiveness to God's continuing revelation.