What my two boys and one girl were told all their lives, now in their mid 20's was "abstinence works every time". I especially drove home to my boys that if they have sex before marriage and get pregnant they are obligated to marry and raise the child. Just remember I would say, if a child is born to one of your out of marriage relationships you will be linked to that "girl" for the rest of your life, due to the child.
My 27 year old daughter recently told me that she would never have an abortion even if she was raped.
Many women don't want to marry the father of the baby, because they can get money from him without marrying him.