If love, not biology makes a family, when one spouse decides he or she is no longer in love, he or she is entitled to tear apart the marriage and family. No-fault divorce laws across the country allow the no-longer-in-love spouse to end the marriage even the other spouse’s against the objections. The couple may have promised, “as long as we both shall live,” but we know that means, “as long as we both shall love.”

The Sunday after Christmas I walked out of church furious—not part of my original plan. The theme was family as in the Holy Family—Joseph, Mary, and Jesus. In his welcome, the pastor told the congregation, “Love, not biology makes a family.” That made me sit up and take notice. His sermon elaborated. “What is a normal family any more?” he asked jovially repeating his mantra that “Love, not biology makes a family.”

It just slides off the tongue: “Love makes a family.” Who could possibly disagree? After all, as he said, there are lots of blended families where husbands and wives are raising their spouse’s children. These families have come together because of love, not biology ergo “Love, not biology makes a family.”

I can’t help wondering how many other Christians including readers of this column believe this sentimental twaddle or at least think they believe it because they’ve never thought it through.

“Love, not biology makes a family,” is among the vilest and most pernicious lies floating infecting culture today. And it’s a particularly good lie since it contains more than a grain of truth. Marriage begins in love and that’s a good thing. Children should be conceived, welcomed, and reared in love. Lack of love indicates a failing family and children cared for out of duty rather than love don’t thrive. The lovingly sacrificing for a spouse’s biological children should be applauded, not condemned.

But consider the cultural and legal outcomes of “Love, not biology makes a family.”

Take opening marriage up to same-sex couples. Who cares about biology (though they must be called “reproductive organs” for some reason) as long as two people love each other? In fact, “Love makes a family” is a focus-group-tested vote-getter for gay marriage.

“Every child a wanted child,” has been a rallying cry among the pro-abortion crowd for years. If love, not biology makes a family and an unborn child is not loved or wanted, while that child may be biologically connected, but is by definition not part of the family. Thus the unwanted child becomes a dead child.

If love, not biology makes a family, when one spouse decides he or she is no longer in love, he or she is entitled to tear apart the marriage and family. No-fault divorce laws across the country allow the no-longer-in-love spouse to end the marriage even the other spouse’s against the objections. The couple may have promised, “as long as we both shall live,” but we know that means, “as long as we both shall love.”

Finally if love, not biology makes a family, no one can object to polygamy (one man with multiple wives), polyandry (one woman with multiple husbands), or polyamory (multiple “spouses”—male, female, or any combination). Logically, if love, not biology makes a family, anything goes as long as the people involved love each other. (Demands for polyamorist rights are on the way. Expect them.)

The other great error and irritant at church Sunday was confusing “normal” with “normative.” “Normal,” the word he used, describes what is typical. “Normative” describes what ought to be. Thus, it is “normal” to overeat during the holidays—most of us do it. But because it’s unhealthy overeating is not “normative”—that is, no one should do it.

A “normal” family in America today is a question of demographics. Families comprising a married man and woman and their biological or adopted children are a shrinking segment of the population. Single moms with one or more children from one or more men are a growing segment as are blended families. Count them, crunch the numbers, and solve for “normal.”

But to go on with a kind of fuzzyheaded “whatever is is right” to treat the normal as normative and even celebrate it isn’t even an intelligent form of relativism. It’s just dumb.

You may hate your mom, but she’s still family. You may not be speaking to your brother, but he’s still family. You may have a friend who is closer than a sister, but she’s not family. You may be cohabitating with someone you love very much, but you’re not family. Sorry.

What is normative? A family is still a group of people related by marriage, blood, or adoption as it has been pretty much since Genesis 1 and healthy families are marked by love. Remember that the next time someone tries to sucker you in with what amounts to little more than a shabby little advertising slogan.

This article appeared on the Institute on Religion and Democracy’s blog and is used with permission.