That is not, in fact, the generally accepted main meaning of the phrase. That is one narrow subset of the larger group of women who are single mothers.Josh wrote: When I say “single mother”, I mean “single mother by reason of choosing fornication”; this is the generally accepted main meaning of this phrase. It is acceptable to speak in generalities and not to muddy the waters with every edge case you can think of.
For example, we can turn to Pew which does surveys on this topic:
Single mothers are made up of two major groups: one consists of mothers with children from a previous marriage, and the other consists of mothers who have never been married. There is also a small group of mothers who are married but whose spouses are not living in the household.
and even if you restrict the discussion to women who have never been married, those who became single mothers through "fornication" as you put it are yet just a subset of that category. Some became single mothers through adoption. Some became single mothers through rape and incest. Some became single mothers through IVF, and some became single mothers through family guardianship situations.
Furthermore, there is no practical way to segregate single mothers based on the circumstances surrounding the birth of the child and have punitive policies for single mothers who got that way through means of which you disapprove, but supportive policies for those who got that way through means of which you approve. There is no scarlet letter that gets imposed on the birth certificates of some children but not others. We dispensed with such nonsense several centuries ago. And attempts to re-introduce that sort of thing would almost certainly be unconstitutional.

