Crumpet - The single mother may well work her socks of to provide for her children. BUT, who looks after the children? Children are only at school for 9 months of the year and for six hours a day. Who looks after them when they're ill and when they're on school holidays? Who is there for them ALL of the time. This is the problem I have seen that single mothers have. They cannot be at work and looking after they're children. It is not possible and few have the kind of wages that can afford a nanny and few have the kind of family support that mean that children are looked after ALL of the time. ALL of the time is what it takes, whether we like it or not, children need 24 hour a day guidance, care and protection from themselves and from others.
It takes two devoted parents to look after children. Those who 'make it on their own' are either lucky to have well be haved kids, or have family support.