My guess is that people are downvoting due to the assumption/stereotype that HIV is associated with homosexuality. While it's true that HIV is more prevalent among men who have sex with men in the US[0], some still think of HIV as "the gay disease", which it is definitely not, and the stereotype contributes to stigmatization of homosexuality.

That may not be what you intended, but it's one way of reading your comment that can come across negatively.

[0]: https://www.hiv.gov/hiv-basics/overview/data-and-trends/stat...

Thanks for answering.

Unfortunately in the population studied (white americans) HIV is far more prevalent in men who have sex with men (>70% of all new infections) than in heterosexual men and women. If your two populations vary significantly in any factor you need to control for it or make sure you rule out that it is significant - this is science 101.

Having read the paper and authors notes, it appears that facial fat differences are unlike to be the signal being detected.

You only need to control for it if the total number of infections is a significant percentage (probably somewhere around 1-5% depending on significance level) of each group population - otherwise you'd have to control for anything and everything and statistical field studies would be completely impossible to allow for any conclusions (while as it is it's just really hard).

This is true, but you should at least make an effort to rule this out. The really hard thing in science is not fooling yourself by overlooking something important.

Didn't vote but they looked at men and women - hence if it found lesbians with some sort of accuracy your HIV treatment hypothesis doesn't work - I'm pretty sure lesbians get HIV at a much lower rate than gay men or drug addicts. It also seems your hypothesis presumes the vast majority of gay men have HIV infections. I didn't bother looking it up, but both those assumptions seem pretty faulty from memory.

Yes lesbians are at a reduced risk to being infected with HIV than heterosexual women.

It is not my hypothesis that weight differences is the signal being detected, it is the GPs. I was just pointing out that facial fat may not correlate with weight in the different populations studied.