Each girl does have a favor stat, in addition to the "Company Favor" currency
Evil13 was talking about. From what I remember, to increase a girl's individual favor:
- Win at poker, and give them back their clothes 'for a latter favor'
- At the pool, put on sunscreen when they are in the lounge chairs (without getting pervy)
- Help them bench press at the gym
- When you turn in sperm samples, I think you also get individual favor with the girl whom you give it to.
I'm sure there are others, and some of these might not be correct, but I'm pretty sure at least some of them work.