1. I should have read more carefully. Yes, I see now that it was Collins who used the 20% concordance for twins. (I believe the most reputable studies have placed those MZ twin concordance rates at 25%-30%.)

However, my point about Bailey is that he speaks of “heritability”–and I still wonder how or if they have actually established that twin concordance rates for SSA (whatever those rates are ) are evidence of genetic heritability as opposed to biological factors. (Again, perhaps the Sanders/Bailey gene study will help clarify this.) That was the crux of my question.

2. Thanks for the link. I should have mentioned that I did know the results of the study. It has been criticized for its sample (internet responders) and as not really establishing much but praised as offering an interesting line of inquiry for further study.

There have been many who have suggested HLA typing might tell researchers something. I guess that is very expensive? Since Bailey’s major research subject seems to be the etiology of SSA, I wondered if he or Sanders (or anyone else with whom they collaborated) had done blood or HLA tests.

I think this huge DNA study Sanders/Bailey got money for only asked for cheek swabs to collect DNA. Unfortunately, if that is the case, it seems they wasted a great chance for other tests. Yes, I suppose they were limited by money. If they get another grant, they might be able to use the same test subjects for further tests.

WOW! Play into stereotypes much at all?

Pretty much every gay man I know loves football!

Maybe they love football players, I don’t know, but there should be a proportion who actually are into sports. Usually, their interests are in the arts, fashion, body care or intellectual area.

Pretty much every gay man I know loves football! Your theories and ideas simply don’t mesh with anything I’ve observed in reality.

Many men who are predominantly SSA report having been taunted and rejected as kids, for instance for not playing football. But I suspect, in some, stressful events wouldn’t be so obvious and therefore they wouldn’t be recalled in connection with sexual identity development (childhood trauma can pass unnoticed or not remembered). What I’m saying is that vulnerable kids go through stressful events or aggressive environments differently than the rest. This might be primarily because of their genetic/hormonal background, but I wonder how much of their adult orientation is a result of them being rejected and growing up apart from their more typical peers. The brain is very plastic at that age and many factors could influence its development. The case of identical twins discordant for sex atypicality sticks out, either as a product of different womb hormones exposure or unique post-natal factors. It’s the unique factors that might be more important for boys who grow up in a typical way, but end up attracted to their own gender in adult age. That was your question, right?

Michael is more accurate to refer to biological factors which may or may not be genetic.

RE: Blood type – Yes – http://www.springerlink.com/content/g15680h356758417/

It might be different for different people. Like genetics playing a greater role in some and a smaller one in others. I’m saying that it’s not necessarily evident that it must be only one factor in all cases. The case of men who weren’t sex-atypical when they were boys, but still develop as same-sex attracted men to some degree seems to argue in favour of something other than sex atypical genetic influences on development.

Thanks for the clarification.

Two additional things–if you should get a chance to correspond with Mike Bailey again:

Bailey says that the 20% concordance figure strongly suggests that there are “hereditary factors” and then of course he goes on to say that this figure also suggests that because the concordance is not 100% there must be other factors other than DNA involved.

1) I was wondering why he chooses the word “genetic” to account for the 20% concordance since things like shared womb events would be more accurately termed “biological.”

I am certainly not arguing the point–just wanted clarification. (That is why I wondered if he “knew” something of the gene study, btw because concordance for things with twins can be shaped by biological events that may or may not be related to genetics.)

2. Can you find out if he knows if any study of SSA/OSA has ever investigated blood types and especially HLA types?

Thanks

If I can have my identity and orientation scrambled by my genetic birth condition, doesn’t that innately mean that it’s from that time period and thus could be for others?