a genealogist or historian who studies family history

A surname. / A given name common in a family, or already borne by someone in the family (in the context of naming someone in the family after that family member).

A family having at least one foster child.

The youngest member of an immediate family. / A member of an immediate family who behaves as, or is treated as though they were the youngest member of a family.

A family unit consisting of a parent or parents and their children.

(sociology) A family that is formed when a couple have their first child.

A stepfamily in which both new mates have one or more living children from prior partners.

(sociology) The family in which an individual grows up.

Used other than figuratively or idiomatically: see family, jewels. / (idiomatic, euphemistic) Testicles.

Birth control, especially when carried out by monogamous heterosexual couples.