Some parents chose to put their careers on hold and take charge of their children's development. Either the mom or the dad stay at home and look after the house and the children.
One of the greatest loves in the world is the love of a parent for a child. This love is unconditional regardless of the child. Should it matter that there is no biological attachment?
Teenage pregnancies are usually not planned and very scary to both parents. However when they do happen the parents need more help and support than parents of mature age.