Fatherhood in the 1950s usually meant a distant male who went to work, supported the family, but left the child rearing to mom. Men of this era may not remember having much affection or physical contact from their dads. Today's dads are part of the team and are more committed to fatherhood. Parents are more established in their careers. If career issues are ironed out, children are less of a threat.
Parents feel like they have time for both their career and a family.
Parents are also more financially stable. They probably own property or a house. This is one less financial burden. This also means that they can probably better afford quality child care. Older parents say they are more patient, calm, and better able to go with the flow than they were when they were younger.