And that may not happen often. But teen boys have a lot of pride. It is not like they will always tell what is on their mind. And sometimes parents have to accept that they just don't want to talk. Expect your son's cues to be more subtle than your daughter's.
Girls are often more open to discussion than boys.
Be open to talking, even at odd hours, about his interest in anything from sports to girls. React to what he says without overwhelming him with comments Don't make a big deal about his having talked to you. Don't make him feel criticized or patronized or ashamed. Answer his questions honestly, even if they make you uncomfortable. Don't berate yourself for missing a cue.