Two couples and 3 types of mixed race babies

This is the introduction to the lifestyles of these 2 couples. One couple is a black man and woman. The other is a white woman and a biracial man whose mother is white and father is black. The father is never known until the babies are born when it is apparent. The women use reliable contraception as they please but the men normally do not know if they are using it or not. The women prefer to not be in the same state of pregnancy at the same time and usually are successful at it so that one baby is not born and another one a few days or weeks later. More details in Chapter One. Comments and suggestions are welcome and hopefully appreciated.