Guys, Why does he keep glancing at my crotch?

So I have this male coworker at this new job I’m working at who keeps giving glances to my crotch area, but he generally avoids me most of the time, avoids eye contact with me, if I enter the room, he leaves. I just don’t understand and maybe it’s obvious but I’d like some clarification from a male as to why he does this.

Guys, Why does he keep glancing at my crotch?
Post Opinion