Parenting is the ultimate long-term investment. Be prepared to put far more into it than you get out of it, at least for some time. Given the structure and stresses of contemporary North American society, the happiness of couples plummets the minute they become parents. And it gets worse before it gets better. In the long run, however, it can be the most rewarding job of your life.
From talking and reading to infants to making values clear (best done in conversations around the dinner table), parents exert enormous influence over their children's development. They are, however, not the only influences, especially after children enter school. It is especially important that parents give children a good start, but it's also important for parents to recognize that kids come into the world with their own temperaments, and it is the parents' job to provide an interface with the world that eventually prepares a child for complete independence. In a rapidly changing world, parenting seems subject to fads and changing styles, and parenting in some ways has become a competitive sport.
But the needs of child development as delineated by science remain relatively stable. There is such a thing as overparenting, and aiming for perfection in parenting might be a fool's mission. Too much parenting cripples children as they move into adulthood, renders them unable to cope with the merest setbacks, and is believed to be a major cause of failure-to-launch syndrome.
There is such a thing as too-little parenting, and research establishes that lack of parental engagement often leads to poor behavioral outcomes in children, in part because it encourages the young to be too reliant on peer culture. Ironically, harsh or authoritarian styles of parenting can have the same effect.