“Children who experience their father’s love are often more emotionally stable, less angry, have better self-esteem and have a more positive worldview,” says Ronald Rohner, Ph.D., a psychologist-anthropologist at the University of Connecticut, who for the past forty years has been studying the effects of father love on children’s development.

Although researchers are just beginning to study the children of involved fathers, there is a mountain of research on the children of absent fathers. Those children are at a higher risk for school failure and dropout, drug use, teen pregnancy, delinquency and teen suicide. On the flip side, having an involved father can have significant, positive effects on a child’s development.

Active fathers are good at answering questions children naturally have about the world around them; they play and interact with their children, as opposed to just caring for their needs.

An active father also provides guidance and discipline when they set healthy limits and enforce them. Researchers report that fathers who value education have children who do better in school than those fathers who do not value education. One study found a correlation between children's reading levels to the amount they saw their fathers reading in the home.

Even six-month-old babies score higher on mental and motor development tests when they have an involved father. The same group of babies handle stressful situations better than babies with dads who aren’t as actively involved. Later these “active dad” children score higher than age-level scores on verbal intelligence tests, and show increased self-esteem and social adjustment.

In the animal kingdom, in 90 percent of birds and the majority of fish, the fathers care for the young. Mammals are the only major group of vertebrates in which mothers are more involved.

Among mammals, 90 percent of fathers take off after conception or birth. But the offspring usually are either self-sufficient from the start or can survive with the sole care of the mother.

In our society, the father’s role is evolving. A generation ago, families were often dominated by mothers. Dad was a vague presence that was held up as a threat: “Just wait ‘til your father gets home!” Now more families feature Mom and Dad sharing the chores and rewards of parenting. These days Dad is likely to push the stroller to the playground for playgroup time, or bring Junior to the pediatrician.

According to census figures, one in four dads cares for his preschooler during the time the mother is working, and the number of children being raised by a primary-care father is now more than 2 million and counting.

Science is finding that there is more to fatherhood than choosing to be a nurturing parents—biology plays a part too. New research suggests that a man’s hormones may play an important role in helping him experience this full range of emotions, especially in becoming a loving and devoted dad. In fact, it offers the first evidence that to nurture is part of a man’s nature.

Testosterone is the hormone associated with masculinity, and definitely plays a part in conceiving a child, but studies are finding that fathers continue to go through hormonal changes alongside their pregnant partners. These hormonal changes may be part of what turns men into fathers, often showing a significant drop in testosterone levels after the birth of a child.

Scientists suspect that these hormonal changes “let the nurturing side of men come to center stage,” says UC Riverside psychologist Ross Parke, Ph.D.

Parke believes that the research suggests something even more radical: “Men are much more androgynous than we think. We have the capability to be aggressive and nurturing. The traditional view of men as predominantly aggressive really sells men short and denies their capability to experience the range of human emotions,” he suggests.

Once these hormonal changes have laid the ground work for a nurturing father, the more opportunities a dad has to provide daily care for his child, the greater the bond he can develop with his child. This care can be bathing, dressing, feeding or changing diapers in the early years, and progress to playing sports, helping with studies, and talking with children as they get older.

Fathers interact and play differently with their children than mothers do, and that difference encourages kids to safely explore the world. Fathers may vigorously bounce and lift a 1- or 2-year-old in rough and tumble physical play; mothers may prefer to play conventional games like “peek-a-boo,” offer an interesting toy, or read. Fathers’ play appears to be more physically stimulating while mothers are more interested in teaching.

One researcher noted that about 40 percent of a father’s time with his young children was spent in play in contrast to about 25 percent of the mother’s time. Even though fathers may spend less total time in play than mothers, their type of play and their apparent interest in that type of involvement make them attractive play partners.

“Fathers are more likely to encourage their kids to tolerate frustration and master tasks on their own before they offer help,” says Kyle Pruett, M.D., a child psychiatrist at Yale.

Just because men and women approach things differently doesn’t necessarily mean one is better than the other. In fact, the differences in parenting are healthy for children, developing their cognitive and social skills. For a child’s fundamental development, active parenting is key.