How come she gets hit on more?

My Mother in law is very young looking. She came to an event with us for my husband recently and his friends/other members started hitting on her so obviously. She's in her early 40s. I used to be into modeling and am tinier than her, and a little curvier and they rarely hit on me. His dad was outside when they did it, but they even accused her (teasingly) of being a "child bride" and thought she was my husband's sister. It really makes me feel bad about myself, because when we go places she is the one being flirted with and not be and I am 19 years younger! What's the deal? I have long hair, and look like Gretchen Wilson the country singer and only get flirt with by losers.