The children of college graduates are more likely to be healthy and perform better at school. A parent's job is to prepare a child for school and keep them healthy. Therefore, college makes students better parents.
Mothers with a university degree are more likely to give birth to a healthy baby. They are more likely to ensure their child is reared at a healthy weight. By the time the child enters school, it has a higher probability of performing better at school and being able to read at the age of 5. The children of college graduates are also more likely to participate in extra-curricular activities. It is a parent's responsibility to give their child the best start in life, both in terms of health and education. Therefore, college makes graduates better parents.
A parent's sole responsibility isn't the health and intelligence of the child. A parent's responsibility is also to raise a happy child, to raise a child that feels loved, to keep a child in a home, to ensure that the child is well-fed, and to educate the child on right from wrong. A college education does nothing to change these aspects of a mother or father's parenting ability. Therefore, it is not accurate to conclude that a college education makes someone a better parent.
[P1] A parent's job is to keep a child healthy. [P2] College graduates keep their children more healthy than non-college educated parents. [P3] Therefore, college graduates are better parents. [P4] Therefore, college makes you a better parent.
Rejecting the premises
[Rejectin P1] This isn't a parent's only job.