Not conclusive evidence, though. If genetics were significant, then I would expect that fraternal twins would show the same statistics as the adopted siblings. Instead, in both cases we see the fraternal twins being higher (although I don't know whether this is significantly higher). In fact, it is exactly this evidence that makes me doubt that genetics is all that significant.
I am not aware that ANYONE is suggesting that genetics is ALL that is significant. This, like many other things, must clearly have some complex set of causes. The gestational environment is another one that seems to have a significant effect as well for example.
The arguement was that homosexuality was a choice. Clearly other things are at play. To what extent and how many of them there are will need further work. However, it is clear that genetics does have a significant effect. With that the case I don't know how individuals are supposed to make a choice about what alleles they get.
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