The United Nations Commission on the Status of Women (CSW) is being pressured to embrace “gender identity” ideology at its annual meeting this week. If successful, the move could erase women from international law and economic development.

Gender identity refers to an individual’s perception of themselves as male, female, both, neither, or something in between. Historically, U.N. efforts to foster gender equality have focused on biological women. If this focus shifts to equality for all possible gender identities, women lose.

Lesbian, Gay, Bisexual and Transgender (LGBT) activists and some Western nations are spearheading the U.N. bureaucracy’s reinterpretation of “sex” in treaties such as the International Covenant on Civil and Political Rights. And although U.N. member-states have never voted to adopt these new definitions, U.N. entities that police compliance with human-rights treaties have added “sexual orientation” to the definition of “sex.”

They have also read “gender identity” into non-discrimination provisions. These actions are neither binding on member-states nor authoritative, but they do influence member-states’ domestic policies and affect their eligibility for development assistance.

At CSW, non-govermment organizations such as Outright International are calling for recognition of gender identity, arguing that they suffer from a “foreclosed definition of ‘women.’” For the first time, the U.N. LGBTI Core Group, of which the U.S. had been a member since the Obama administration, also made a similar statement.

Advancing the notion that gender is fluid is not a priority for women in non-Western countries. Unsurprisingly then, the LGBTI Core Group’s statement received a tepid reception from the global gathering. Accusations of cultural imperialism have often been unfairly cast upon the universal human rights movement. But advancing a progressive ideology that conflicts with a scientific understanding of sex gives critics ammunition to attack the CSW’s noble goals.

If the U.N. begins to treat biological men as if they are women because they perceive themselves to be women, then the discussion of women’s economic empowerment will turn into one about everyone’s economic empowerment.

That defeats the purpose of having separate discussions about women’s roles in the informal economy and as caregivers for children and the elderly, to say nothing of improving women’s access to credit, pensions, and unemployment benefits, a priority theme of the CSW.

Legally recognizing gender identity also endangers women and girls.

In nations that recognize the concept of gender identity, male sexual predators have exploited the laws to gain access to private spaces. In England, this led to sexual assaults against women in prison, and in the U.S. against a 5-year old girl in her school bathroom. This is not to accuse those who identify as transgender of desiring to harm women. But giving men access to female-only spaces removes critical barriers designed to protect women.

The rights of those who identify as transgender must be protected like everyone else’s simply because they are human. But their legitimate claims to human rights are not based on their membership in any particular group, nor should they justify reducing the rights of women and girls.

Furthermore, transgender ideology perpetuates gender stereotypes that feminists have long fought against, such as what constitutes “women’s work” or what sports are appropriate for girls.

Sex is a biological fact, not a feeling. Women and girls around the world face discrimination and harm as a result of historical and cultural factors related to biological sex. Therefore, international law and economic development policy should continue to be based on this reality.

At CSW, the U.S. delegation should focus on advancing opportunities for biological women and girls, as they have rightly pledged to do. Women around the world still need to secure their legal and economic rights, to gain access to quality medical care and education, and to combat violence. To respond to their most pressing needs, the U.S. must protect women from being erased in international law through a radical redefinition of sex.