It looks like all those Brother Crush videos may be onto something. If you are a boy you’re more likely to be gay if you have an older brother.

Above: Brothers by Jude Beck@judebeck on Unsplash.

The New York Post reported: New research found that having an older brother increases men’s chances of being gay, according to a study published Wednesday in the journal Proceedings of the Royal Society B . “The fascinating study estimates that having an older brother increases the odds of being gay by 38 percent, supporting the idea that a mother’s immune response to having a male child influences subsequent boys,” University of Cambridge professor and statistician David Spiegelhalter told the Daily Mail . “People have endlessly argued about the possible roles of genetics and upbringing, but this clear result fits in neither category.”

Read the full study here.