It was all over the news for the last few days. Scientists from LA got even closer to understanding that sexual orientation is some sort of wibbly wobbly timey wimey stuff.
Interesting question though, will it increase the effectiveness of that particular test in future if parents know that they child has 70% chance to be gay? Basically, if parents, given positive results for their newborn, it will create a certain bias, which in result can increase amount of gays within group of people who tested positive after birth. Or it can go other way around.
Another thing I can see from that kind of study is that for some people it might be easier to come out of the closet. Considering in majority's perception genetics is something that is set in stone and nothing you can do about it, so they will just "accept their nature".
P.S. Whenever I see research like this one, always ask myself, where do they get so many identical twins. Is there are twin farms somewhere. Shouldn't it already be a book published, something like "Effective Twin Farming: beginners guide" or "Twin Farming for dumb: how your useless children can contribute to future of mankind".