House Speaker Nancy Pelosi introduced the Equality Act in March by grandly alluding to the civil rights battles of the last century. Yet the bill, which would add gender identity and sexual orientation to the Civil Rights Act, risks undermining decades of hard-fought gains by American women.

If enacted, gender identity — defined in the bill as the “gender-related identity, appearance, mannerisms or other gender-related characteristics of an individual, regardless of the individual’s designated sex at birth” — would become a federally protected status. The bill’s single-sentence definition includes no qualifying criteria or nuance.

Already, a biological male, even one who hasn’t begun to physically transition, can assert female gender identity and win obeisance from many public and private institutions.

The Equality Act would add the force of federal civil rights laws to such demands.

The ramifications are enormous.

The purely subjective definition of gender put forward by activists, and accepted wholesale by the bill’s supporters, is a radical one. Yesteryear’s dogma held that transgender individuals identify with the opposite sex and suffer as a result of the mismatch between their physical bodies and their subjective sense of gender.

Today, however, the activists claim that a man who asserts female identity is literally a woman, and vice versa. As the Princeton philosopher Robert George has argued, this is a view of human beings that sharply divides the bodily from the spiritual or mental, then claims that the latter utterly trumps the former.

But hold on. Everything we know about sexual differentiation between men and women tells us that it begins at the chromosomal level from the moment of conception. Sexual difference is ­inscribed in our genetic code. The Equality Act ham-fistedly redefines this basic fact about what it means to be human — at the ­expense of women.

How so? Because our entire system of anti-discrimination laws is premised on bodily sex — that is, on the notion that physical differences between men and women are significant and meaningful in a variety of ways.

Already, high school women who have worked tirelessly in their sport are losing important athletic scholarships due to the unequal competition from biologically male athletes with the stamina and muscular advantages of men.

In Connecticut, transgender students have dominated women’s track and field state championships for two years straight, to the despair of female runners who lose to biological males who aren’t required to use hormones.

At the collegiate level, sports organizations do require hormone therapy to help level the playing field, but this rule would be undone by Pelosi’s Equality Act, placing a glass ceiling over female athletes.

Plus, on issues ranging from athletic performance to job discrimination to bodily privacy (in bathrooms, prisons and interactions with law enforcers), our laws ­assume a sex binary. Indeed, recognition of men’s and women’s differing needs was something progressives used to insist on. In 1975, for example, a Washington Post op-ed noted that “separate places” for women are required to fulfill the “equality principle.”

The author of that op-ed was future Supreme Court Justice Ruth Bader Ginsburg.

Herein lies the problem: The Equality Act takes complex ­issues and distills them into all-or-nothing propositions. It dismisses all efforts to reach equitable solutions that meet the needs of transgender individuals and children suffering from gender dysphoria and instead tramples biological females.

Meanwhile, activists furiously shut down efforts to slow the pace of their radical reforms. Under the Equality Act, health care and mental health professionals would be coerced into providing gender-transition treatments to children and adolescents, despite a growing body of evidence that suggests that in many cases children who claim to be the opposite sex desist by the time they reach puberty.

And what about parents? ­Under the Equality Act, parents could be found guilty of violating their children’s civil rights if they decline to consent to dramatic transition procedures.

Sadly, it seems Democrats aren’t interested in having a serious conversation about gender identity and bodily sex. Their playbook is clear: Drive a wedge between Americans by portraying defenders of women’s (and parents’) rights as bigots from a bygone era.

Women must resist, because this bill is far from equal.

Mary Vought is a Republican strategist. Twitter: @MaryVought