I think many of these posts show a lot of prejudice and belief in stereotypes.
The majority of single person households are the result of marriage and long term partnerships breaking down, and like it or not, even if the father is contributing, the cost of running 2 homes with associated costs such as council tax, rent, utilities is much more exensive than when the family are together and that is going to tax the majority of families.
Of course there are a group of society, who come from broken homes, violent homes, dysfunctional homes, who have been neglected and unloved and to these having a baby who will love you is a lovely thought. But babies have to be loved and cared for to show love and neglected and abused babies cannot show love and the cycle re-occurs.
One thing I have noticed recently is the frequency with which a baby quickly follows a new relationship, in a way one didn't hear of in the past, where new and possibly transient partners seemed to not want children. Is their a belief by some young men that they need to prove their virility and power by getting the women in their lives pregnant, or is it a power play, 'You have had my child' you can never get me out of your life even if we split up'?