Gay people often have older brothers. Why? And does it matter?

Actually, the youngest in a family is often the one who is homosexual/gay. The theory is that rather than having their own children, they then help raise the children of their siblings.

If you want to see some hard Science (no pun intended) or how wide the world of Sexuality really is; may I recommend a book by Lucy Cooke: "Bitch: On the female of the species." It might broaden the concepts on the article above.