Tennis and football/soccer are the two sports gay people most frequent by a wide margin, so it's really no surprise. Why? Probably because the sports are less hyper-masculine, and because the guys look better overall (more trim and athletic looking rather than hulkish).
BTW, there is no such thing as a "gay" sport.
To answer my friends' question, no, I've never had that issue since I'm generally the one being approached. Like you are being approached now. He's into you..............there must be a reason. I guess you're a hottie too
Take advantage of this situation and this hot guy, seems like a nice guy, run with it. Don't allow your head get in the way of potential fun.