The transgender movement is feminism’s worst nightmare.

The latest iteration of this truism comes in the form of the transgender bathroom controversy now swirling in North Carolina. Transgender advocates – and leftists including myopic feminists – insist that men who believe they are women should be allowed to use women’s bathrooms in any business. This, of course, disadvantages women who may be uncomfortable being in close quarters with men as they drop their panties.

But there’s another, bigger problem: using Title VII of the Civil Rights Act of 1964 as an excuse to destroy traditional gender-specific bathrooms actually destroys Title IX of the Civil Rights Act. That means an end to women’s athletics on campus.

Here’s why.

Title VII makes it illegal to discriminate “against any individual” on the “basis of sex.” The text of the law makes it clear what that means:

The terms “because of sex” or “on the basis of sex” include, but are not limited to, because of or on the basis of pregnancy, childbirth, or related medical conditions; and women affected by pregnancy, childbirth, or related medical conditions shall be treated the same for all employment-­related purposes, including receipt of benefits under fringe benefit programs, as other persons not so affected but similar in their ability or inability to work, and nothing in section 2000e-2(h) of this title [section 703(h)] shall be interpreted to permit otherwise.

Obviously, none of this applies to men who believe they are women. But the courts have been gradually rewriting the definition of “sex” to mean“subjective self-definition of sex.” This is the legal equivalent of rewriting “equal protection” to apply to objectively different behavior (say, marrying someone of the same sex as opposed to marrying someone of a different sex). The left constantly rewrites clear legal language in order to achieve their objectives.

But in this case, the left’s transgender agenda is likely to blow up in their face.

That’s because of Title IX of the Civil Rights Act, which prohibits sex discrimination in education, and which has been used to keep failing women’s sports alive at universities, or force men’s programs to shut down. Title IX uses the same language as Title VII: “No person in the United States shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any education program or activity receiving Federal financial assistance.”

So, if “sex” now means subjective sexual self-definition, there’s no rationale for separate men’s and women’s teams anymore. Men could take advantage of this rule to play on women’s teams, thereby destroying the rationale for Title IX as applied to sports funding. If men are sick of watching as their baseball teams get cut in order to sponsor women’s volleyball teams, they could simply apply to the women’s softball teams and outcompete all the women. If men and women are supposedly the same in all respects, and if the Justice Department feels that you need not even legally change your sex or surgically alter yourself to imitate members of the opposite sex, why can’t men simply walk on for Geno Auriemma at University of Connecticut? That would spell the end of women's sports, given that the best boys' high school basketball teams could easily defeat a typical WNBA squad.

Feminism states that women deserve equal rights. For the past few decades, the only debate here has been the definition of “equal.” The DOJ just opened the debate on the definition of “women.” That’s far more dangerous for women than anyone else.