I do agree with this- it is largely to do with your upbringing, which often explains why people are the way they are. I think Megan is needy and desperate for a family because her own family are so keen on family themselves. On the show when Megan was with Dylan, her mum and her sister were saying how important family was- they seem close knitted so it does seem like Megan just values family over anything else because of her family's attitude.
However, I don't think parents can be blamed for their children's mistakes fully- people are their own person, and your upbringing is only part of you. I lived with my mum, who never went to university and barely finished college and witnessed her go through an abusive relationship with my sisters dad, yet I am still at university with my own place. It's ashame that these girls do seem to have gone down the wrong route though. It's hard when you have no encouragement and no one to look up to. However, I think all of them are fairly good mums even if their lives are so full of drama !