it's not related to the single status of the mother but to her social class
Manners and respect have no social class.
A good example was during the "Ferguson Riots" when t.v. news camera's were on it.
One poor 'black' single mother saw her 17 year old son with his hoodie and sunglasses on the t.v. shouting at the police and protesting in downtown Ferguson with a gang of hooligans.
The mother got on the bus and went downtown to get her son.
It was captured on t.v. of her going up to her son kicking him in the behind, slapping him in the face a couple of times and grabbing him by his ear taking him home.
An interview with that mother and son was done the next day on t.v. with the son apologizing publically to the police for his foul mouth and actions.
His mama stated that she did not want her son getting shot by the police and had brought her son up better and as long as he was living under her roof he would address adults as, yes mam and no sir.
This proves that it is all in how you are brought up no matter single mother, social class, color, poor, etc. and not a pity party for an excuse to live in denial.
When I see out of control kids my first thought is, "I wonder when the last time was that someone who cared took him/her to church and fishing. :-]