For me and for most men, burdened with frailties and shortcomings, becoming a father is as close as we’re likely to get to participating with God in creation.

Let’s start with the obvious: Becoming a father changes a man’s outlook. It focuses his attention. It typically encourages him to work harder and think more about the future. It tends to make him less selfish. He’ll tend to spend less time staying out late, tomcatting around with his buddies, and more time trying to be a regular citizen and a good guy. Many studies have documented these changes.

Becoming a father also changes a man’s body. Both the sexual bond with the mother and the conception of the child appear to reduce a man’s testosterone levels, which makes him more cooperative and less ornery and aggressive. According to a new study, "Mother Bodies, Father Bodies: How Parenthood Changes Us from the Inside Out," by my colleagues Kathleen Kline and W. Bradford Wilcox, a fascinating cluster of brain and hormonal changes, all of them pro-social, appear to help shape and guide men’s transition to fatherhood. Some of them occur before the child is born! Everyone knows that becoming a mother changes a woman’s body. But who knew that becoming father also changes a man at the biological level?

Third, becoming father changes a man’s society. There are many individual exceptions, of course, but married fathers tend to be more likely to contribute positively to society and less likely to hurt others and themselves. Even taking into account what researchers call selection effects – the fact that while married fatherhood makes men behave better, it’s also true that better-behaved men are more likely to become married fathers – many careful studies have found that in-the-home, bonded-with-the-mother fathers do significantly more than other men when it comes to helping society and staying out of trouble. For starters, their own children, compared to children from one-parent or stepfamily homes, do better in school, get into less trouble, and lead happier lives.

Consider the problem of teen pregnancy. Numerous studies find that a father in the home is more important that nearly any other factor – more important than race, income, neighborhood quality, or mother’s educational status – when it comes to the girl’s avoidance of teen pregnancy and early sexual activity. Why? Partly because of the father’s outlook: He wants to protect his daughter. And partly because of his body: A father’s pheromones – chemical substances secreted by the body that serve as stimuli to others – seem to slow down the onset of puberty in his daughter. Who knew? It’s probably impossible in this case to disentangle the social from the biological dimensions: the two seem to sway together, like elegant dancers.

Finally, becoming a father changes a man’s relationship to the eternal. True fatherhood – not the act of insemination alone, but the way of living – links me as a man to what the great psychologist Erik Erikson called generativity, the sense that I’m a part of new life and therefore part of the ongoing renewal of the world. In this way, fatherhood makes life meaningful. It can connect a man to the transcendent, helping him to recognize and respond to some of life’s most important questions. Why am I here? Do I matter? What if anything will I leave behind? For me and for most men, burdened with frailties and shortcomings, becoming a father is as close as we’re likely to get to participating with God in creation.

American fatherhood is currently splitting into two. If you’re growing up today in upscale America – if both of your parents graduated from a four-year college – the odds are strongly in your favor that your father lives with you, is married to your mother, and is highly motivated to help you succeed and thrive. But if you’re in the 70 percent of America that is not upscale, the odds of you having such a father in your life are strongly against you and getting worse all the time.

The U.S. today is a place of growing inequality and, for so many, diminishing opportunity. We’re becoming two societies, separate and unequal. And the great dividing line between the haves and have-nots today is not the color of your skin, or where you live, or the language of your parents, or the God you worship. It’s whether you have a hands-on, married-to-your-mother father.

That’s why, for Father’s Day 2014, we honor American fatherhood not only by marveling at its meaning and honoring its presence, but also by looking at the many places and hearts in our society where it so desperately needs to be, but isn’t.

Read "Parental parenting: Learning how to be a dad."

David Blankenhorn is the founder and president of the Institute for American Values and the author of Fatherless America and The Future of Marriage.