As a follow-up to my post on family structure, this table is more specific since it indicates what percent of families are biological, step, cohabiting, or single-mother. It varies a bit by whether you interview a teen or a parent because of ambiguity of definitions (2009. Demography 46:85-101). The specific question I want to answer is, what percent of two-parent families have kids with their biological father.
We calculate that by dividing the percent in biological families by the percent in all two-parent families. Eighty-two percent of two-parent families have Dad with his biological kids. (And this is an underestimate since a small percent of stepfamilies are biological father-children families.) You can see it is more of a problem among Hispanics and especially blacks. Some commenters seem to think the biological family is quite rare, and men shouldn't get married and have kids because they will generally lose them.