How do I get guys to stop Leering/staring at me?

I'm a twin and whenever we go out guys always stare at us I usually dress in an oversize t-shirt and jeans so I don't dress provocatively and They just keep staring at me and it's really irritating. If they come up to talk to me I notice that they stare at my chest :/ when My parents introduce us to their friends sons I notice them leering I just want it to stop what do I do? And please nothing like gaining weight and becoming disgusting