>Perhaps most convincing is that over 50% of identical twins where at least one was homosexual, the other was as well

Strange........what I get from that statistic is that a significant percentage of identical twins do not have the same sexual orientation. If it were a purely a matter of genetics then I would expect 100% to have the same orientation.

There is clearly something else at work. Where that comes from I don't know. I'm reasonably sure it is not a conscious choice; just as left/right handedness is not a conscious choice but is also clearly not purely genetically controlled.