While some are necessary to complete missions, each girl comes with a variety of perks and benefits.There are six girls in the game that you can pick up.
Dating any of the six girlfriends is not required for 100% Completion with the exception of Millie Perkins who can be killed on the first date.
After a certain number of successful dates, Carl may be invited back to her place for "coffee" (sex), and once the relationship status is maxed, Carl will receive a unique outfit from the girlfriend.
Welcome to the Grand Theft Auto: San Andreas section, a brand new section that will cover San Andreas in as much detail as possible.
Denise is first encountered during the mission Burning Desire, whilst Millie first appears during Key To Her Heart.
The other girlfriends, who are encountered during gameplay rather than being attached to missions, are Michelle Cannes, Barbara Schternvart, Helena Wankstein and Katie Zhan.