Green’s Dictionary of Slang

family n.2

[note the prostitute’s phr.: ‘Sleep with that pig and you’ll end up with a family to feed’]

(US) crab lice.

[US] (ref. to 1940s) B. Rodgers Queens’ Vernacular 55: crab lice infecting the pubic areas [...] family (fr pros sl, ’40s: ‘Sleep with that pig and you’ll probably end up with a family to feed’).