MRI scans of 25+20+25+20 = 90 people have supported a proposition that many people have "known" for quite some time: homosexual men's brains are structured like the (straight) female ones and lesbians' brains are structured like the (straight) male ones.
The researchers from the Karolinska Institute, Sweden - where the medicine Nobel prizes are decided every year - have shown that the straight male and lesbian brains are larger and left-right asymmetric. The straight female and gay male brains are smaller and symmetric.
The amygdala seems to be the region of the brain - responsible for emotional reactions (both CPU and RAM) - that shows the identity most efficiently. It is enough to look whether the nerve connections are mostly in the left half or the right half: you find out that the straight men and lesbians have connections mostly on the right side of the amygdala and vice versa.