Genes and Jeans

How in the world is it humanly fair that a man can devourer like 3,000 calories in one sitting and not gain a pound, probably even loose weight from the 3, 20% more Dorito bags, and a woman gains weight just by looking at the food? Or why do they not even have to bother trying on jeans. They know their size, its one size, pick the pair out they want and are out the store. We have to haul 30 pairs in with us, wait in line for a fitting room, meet the 8 piece limit, bring back out one pair in order to bring back in another pair to try on, take 3 hours trying on jeans, and still walk out without a pair. Not to mention, that in one pair we might be one size, but get another brand and all of a sudden we have either dropped 2 sizes or gone up 10 sizes. Lovely.