A co-chair of the White House Gender Council voiced opposition to red state pro-life legislation Friday, decrying lawmakers who believe "pregnancy starts at fertilization."

President Biden signed an executive order Friday protecting access to abortion and contraception services after the Supreme Court’s decision to overturn Roe v. Wade, saying the high court and Republicans have underestimated the "power of American women." 

He predicted they will turn out in "record numbers" for November’s midterm elections to "reclaim the rights" taken from them.

In a subsequent press briefing, White House Gender Council Co-Chair Jennifer Klein blasted red states for pushing legislation that implicitly or explicitly states pregnancy begins at fertilization. 

ABORTION DECISION DRAFT LEAKER'S IDENTITY REMAINS A MYSTERY AS SUPREME COURT ENDS ITS TERM

Jennifer Klein

Co-Chair and Executive Director of the Gender Policy Council Jennifer Klein speaks during a daily press briefing at the James Brady Press Briefing Room of the White House March 8, 2021. (Alex Wong/Getty Images)

"Emergency contraception is at risk in states across the country now," Klein said of red states' anti-abortion legislation. "Partly because there are states that are passing laws that say pregnancy begins at fertilization and that puts a drug like emergency contraception at risk."

There is no universal legal or scientific definition for when pregnancy begins, but the consensus among polled medical professionals trends towards fertilization.

WHITE HOUSE GRILLED ON PROTESTERS TARGETING JUSTICE KAVANAUGH AT DC RESTAURANT

In a 2012 survey for the American Journal of Obstetrics and Gynecology it was found that "one-half of U.S. obstetrician-gynecologists (57%) believe pregnancy begins at conception. Fewer (28%) believe it begins at implantation, and 16% are not sure."

Traditionally, pregnancy is measured in "gestational age," beginning from the first day of the pregnant woman's last regular menstruation cycle.

Jennifer Klein at the white house

Co-Chair and Executive Director of the Gender Policy Council Jennifer Klein, center, speaks as Co-Chair of the Gender Policy Council and Chief of Staff to the first lady Julissa Reynoso, left, and White House press secretary Jen Psaki, right, listen during a daily press briefing at the James Brady Press Briefing Room of the White House March 8, 2021, in Washington, D.C. (Alex Wong/Getty Images)

"Pregnancy lasts about 40 weeks, counting from the first day of your last normal period. The weeks are grouped into three trimesters," says the U.S. Department of Women's Health.

According to Planned Parenthood, "In order for pregnancy to happen, sperm needs to meet up with an egg. Pregnancy officially starts when a fertilized egg implants in the lining of the uterus. It takes up to 2-3 weeks after sex for pregnancy to happen."

CLICK HERE TO GET THE FOX NEWS APP

The president said the Supreme Court’s "terrible" and "extreme" ruling to return the issue of abortion to the states after more than 50 years was "wrongheaded."

"Let’s be clear about something from the very start: This was not a decision driven by the Constitution," Biden said. "Let me say it again. This was not a decision driven by the Constitution, and despite what those justices — the majority — said, this was not a decision driven by history."