My daughter was catching up on her college homework. Chapter Ten in her psychology textbook is titled “Sex and Gender.” It covers topics such as gender differences, similarities, and stereotypes. The chapter wends its way from transgender issues to sexual harassment to the glass ceiling, the invisible but real boundary in the workplace beyond which women are not welcome. The book defines sexism as “differential treatment of an individual on the basis of his or her sex.”

As the text points out, more than half of all women in the United States now work outside the home. They are breaking through the glass ceiling and garnering high-profile positions in private industry, government, and politics. There is one domain, however, in which women are increasingly discriminated against and excluded: families.

Ironically, same-sex marriage laws do this in the name of equality. We open our hearts and minds and definition of marriage to include two men, and in doing so we close the door to a wife in the living room, a mom in the nursery, and a feminine lover in the bedroom. We create a crass ceiling.

It’s one thing for two guys to love each other; it’s altogether different for society to endorse this union by granting these two men the status of marriage. A male marriage might not look overtly sexist, but what about the long-term effects? Redefining marriage grants men the legal right to deprive children of a relationship with their mother simply because she’s female. Because she’s “born that way.”  What if this gender discrimination continues?

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Obviously, two men cannot reproduce with each other, but in tandem with marriage comes the right to adopt. If a male couple’s adopted son meets and marries a like-minded guy whose dads commissioned him from a surrogate mother, then we would see an extended family bereft of not only mothers but also grandmothers. On both sides.  Under current law in many states, this chauvinism can continue for generations.

Decades from now, young Marvin can trace his family tree and compare it with that of his pal Leroy. The latter has one mom and one dad, two grandmothers and two grandfathers, four great-grandmothers and four great-grandfathers. Leroy’s family tree is gender-integrated and balanced.

Meanwhile, Marvin lists two dads, four grandpas, and eight great-grandfathers. His family has fourteen men and zero women; it’s gender-segregated and devoid of wives, mothers, grandmothers, and their feminine love.

Of course, we know that babies can’t actually be nurtured for nine months in a test tube using IVF, no matter how many thousands of dollars we thrust at researchers. And despite millions in research, no scientist has ever generated a single ovum. Marvin had to have a mom or he wouldn’t be here. And his parents had to have mothers as well. It’s not that Marvin doesn’t have a mom or grandmothers in his ancestry. These women are invisible to Marvin, but they are real. They were intentionally excluded from his family precisely because of their sex.  This man-made barricade is more harmful than the glass ceiling at work since it prevents children from accessing their own mothers.

Man caves are fun. Man family trees . . . not so much.

Certainly two men have the capacity to love each other. But no matter how much they care for each other, a man will never be a wife. No matter how fatherly a husband is, he will never be an adequate mother.

If two guys fall in love, they can choose to keep their relationship private or make it public. They can even make it official by announcing it on Facebook. It’s their choice. But requesting a marriage license is different.

Marriage is the bond that seals a family together and plants the roots of our culture. Families are the living cells of the great organism of life. Typically, marriage creates new micro-societies: mom, dad, and their children. Marriage is social by nature; therefore, weddings require witnesses.

It is important to note that de-gendered families exclude females not by accident, but by design. Same-sex marriage constitutes sex discrimination and segregation. But I have spent too many years interacting with mothers and children to support the idea of excluding moms from families because of their sex. I love and respect my own mother and grandmothers far too much to fall for the notion that contracting them out of our marriage laws constitutes “equality.” And even if I didn’t have the firsthand experience of knowing so many women exhibiting their feminine genius, I would disagree with gender discrimination in principle.

After all, if gender is not important in marriage, when on earth is it important? Will the same progressives clamoring for male marriage now seek gender quotas in the years to come? Will future feminists fight for the right of children to know their mothers?

To be fair, same-sex marriage laws grant women the same right to segregate family trees and the same power to deprive their children of fathers. But this doesn’t advance equality. That’s simply the debunked “separate but equal” argument in new, gender-segregated clothing. Again, I know too many dads and I honor my own father far too much to endorse writing them out of generations of children’s lives for the supposed crime of being born male.

Of course, same-sex marriage lobbyists can argue that the likelihood of entire branches being segregated by sex is slim. (I sure hope so.) Yet they dare not criticize the right to create gender-segregated family trees, because doing so would automatically refute their case. After all, redefining marriage is predicated on the theory that gender diversity is unimportant in marriage. Supporting gender integration would automatically plant them on the side of pro-gender marriage.

When confronted with Marvin’s ancestry, same-sex marriage activists can only applaud as they continue to support excluding either husbands and dads, or wives and mothers from homes. They consider this such an important benefit to society that they have persuaded judges or legislatures in sixteen states and a handful of countries to enact laws enabling gender segregation in families for generations.

That’s not marriage equality. That’s same-sexism marriage.

Perhaps you noticed that the words gay, homosexuality, and sexual orientation have not been used thus far in this discussion about marriage.  Why?  Because we don’t have to talk about gay sex. When we defend marriage, we don’t need to debate whether homosexuality is sinful, or “icky” as Bill Maher sarcastically put it. Let Dan Savage talk it to death. We can keep the conversation rated G by focusing on gender.

Progressives like to portray SSM as strictly a gay rights issue. However, at its core, marriage is about gender diversity and children.  So when your neighbor says she supports marriage equality because she wants to be on “the right side of history,” ask her, “What is ‘right’ about gender discrimination?” Gender segregation belongs in public restrooms, not families.

Let’s keep our ancestry honest and inclusive; let’s keep our families intact and thriving.

Don’t let your friends fall for same-sexism marriage. The gay rights lobby has fought long and hard to present marriage as discriminatory and unequal by focusing on sexual orientation. It’s as if they can’t see the legitimate concerns of children for both a mom and a dad because of their focus on homosexuality. Bring the conversation back to gender and children. Marriage welcomes everyone—husband and wife, father and mother, grandfather and grandmother, as well as their fruits: children.

As SSM advocates scatter seeds of gender alienation, we can focus attention on our collective family tree, which is inclusive and integrated. Every time you’re online reading an article that supports same-sex marriage, prune away the focus on homosexuality in order to shine a light on the roots of gender discrimination. Call attention to the fact that these are gender-exclusive unions. That they are missing one half of humanity. They deliberately deprive children of either a mother or a father. Their grandchildren will therefore lack either a grandmother or a grandfather. If they call it marriage equality, ask why treating the children of gays differently and banishing their mothers from the home is equality.

And when they refer to same-sex marriage, invite them to join the right side of history by rejecting sexism and supporting pro-gender marriage.  Because gender matters to everyone, including homosexuals, as well as their children and grandchildren and great-grandchildren . . .