A Computer will go down on you without dinner and a movie. One to actually change it, and 3 friends to brag to about how he screwed it. When it's time to go back to his childhood, he's already there. Both are dispensable. The sofa doesn't keep asking for beer.
Men are taller.
The good ones are always taken and the ones that are left are handicapped. To allow the Oxygen to flow to his brain. By sucking in their stomachs every time they see a young woman in a bikini. Because they should be. When the crew gets lost in space, at least, she will ask for directions.