Do you check out girls in a way that they would notice? Because girls might check out boys while hoping the boys wouldn't notice the same way (I assume) boys check out girls. But I think it depends on the circumstances as well. For example, if I'm walking with friends I'm less likely to look at boys as I don't want my friends noticing the boys not looking my way (or at us at all). If I'm by myself am more likely to check boys out but do it less as am tired of them either not seeing me or pretending not to (and before anyone says, I am not unattractive) so depends quite a lot on the boy as well (at least for me, whether he looks approachable or distant).