It was cut from the game, just not with the surgical precision you would expect, but rather removed with a hammer. To progress with Carol simply visit her home in the afternoon.
It's always 100%, there are a few 1shot characters and 3 of the recurring characters can be impregnated, but there is no visible change. The characters are the chemistry teacher(one time event, it's separate from her story if I remember right), Carol and the office lady from the police station during Carmen's quest(you actually need to impregnate her for the quest).