For 25 years nearly three-quarters of black children have been born out-of-wedlock. However, 36% of births to whites are now to unmarried parents – up from 7.9% in 1975. In fact, 53% of all births to women under age 30 are to single women.

Why? Are high school kids so drenched in sex that marriage is on no one’s horizon? No. According to the Annual Report on Family Trends by Patrick Fagan of the Family Research Council, the percentage of high school students who have had sex has dropped from 82% for blacks in 1991 to only 60% in 2011; and it has fallen for white kids from 50% to 44%.

The deeper problem is the drop of family income of everyone.

The inflation adjusted average income for all men rose from $20,000 to $35,000 by 1970, inched up to $37,500 by 2010 but dropped to $34,500 in 2012. Even those with professional degrees have taken a hit. They earned $111,000 in 2000 but $100,000 in 2012. The proportion of middle-income households dropped from 61% in 1971 to only 51% in 2011.

Falling income makes people hesitate to commit to marriage – particularly those in “Middle America,” who are 25 to 60 with a high school degree. Four decades ago, these moderately educated Americans were as likely as college graduates to marry. Only 13% of high school educated mothers had children outside of marriage in the 1980s. That figure is now 44% - close to the least educated mothers, 54% of whom had unwed births.

However, the major marriage-killer is cohabitation. This assertion would surprise many young people who go to weddings where two-thirds cohabited first. However, of more than 8 million couples living together last year only 1.4 million married. Four out of five broke up.

And 41% of them had a child. What are the odds are that a woman with a child will marry? Slim. Most men want to have their own child with whoever they marry, not another man’s.

What can be done? Here are three answers.

While incomes have fallen in recent years, those who marry will fare much better than those who remain single. Median family income, adjusted for inflation of married couples grew steadily from $28,000 in 1947 to $55,000 in 1970, on up to $80,000 in 2010. In just two years, it fell to $75,000 – but that’s good income.

Second, ask your pastor to preach a sermon on cohabitation. I have asked hundreds of pastors if they have ever preached a whole sermon warning about the dangers of living together outside of marriage. About one hand in 50 goes up. It is easier to preach on Abraham – and far less useful to a generation who believes they ought to “test the relationship” first.

As one marriage educator put it, “You can’t practice permanence.” The pastor should say, “The best way to test the relationship is by taking a test – a premarital inventory which asks the man and woman separately whether they agree or disagree with 150 statements like `I go out of my way to avoid conflict with my partner.’

“Then the couple should sit down with a trained Mentor Couple to discuss the issues which are surfaced.”

Finally, the government should stop subsidizing unmarried couples to have children. The cohabiting woman with a new baby has the benefit of her partner’s income as if married. She should not be given $25,000 of subsidies, as if she were raising the child alone. For cohabiting couples with children, governors should encourage them to marry by not cutting benefits if they marry for two years, with subsidies tapering off over three more years.

The states that subsidize marriage will have rising marriage rates, falling unwed births, and save billions of taxpayer dollars.

Mike McManus is President of Marriage Savers and a syndicated columnist, writing Ethics & Religion weekly. He can reached here: mike@marriagesavers.org