PARIS — Gwendoline Desarménien wanted to have a baby. But as a single woman in France, she was by law denied access to in vitro fertilization.

And so Desarménian drove from her home in Montpellier across the border into Spain, where she found a clinic and a hotel where she could stay during her treatment.

The expedition was expensive, costing Desarménien, a human resources officer of moderate means, about $6,600. But one of the hardest parts, she said, was feeling that her country thought she was doing something wrong.

“All these restrictions that we have show a lack of an open spirit – that we still have difficulty evolving and modernizing,” said Desarménien, 43, whose daughter is now 1 1/2. “I think French society has difficulty realizing that the family isn’t just a father and a mother. And if we are in the process of advancing, it is slowly.”

President Emmanuel Macron is trying to encourage that advancement by changing French law on reproductive technology. It’s his most significant social reform to date. And it would bring France in line with what is legal and routine in many other European Union countries. Ten EU nations permit the treatments for single women and lesbian couples, and seven others restrict it to single women.

“The criterion that defines a family is the love that unites a parent and child,” Health Minister Agnès Buzyn said when introducing the bill in Parliament.

But the effort has produced a backlash – which should be visible in protests planned for Sunday in Paris and across the nation.

While French liberals say the question is about basic rights for women, conservatives say it’s about children’s rights to have a father.

The government, said far-right agitator Marion Maréchal, is trying “to voluntarily deprive a child of a father or to transform him and the mother who carries him into a consumer product.”

France currently limits access to medically assisted reproduction – including artificial insemination and in vitro fertilization (IVF) – to heterosexual couples who are married or have been living together for more than two years.

The revised bioethics law proposed by Macron’s government would extend access for single women and same-sex couples. Women under 43 would be eligible for artificial insemination and up to four rounds of IVF, fully covered by the French health system. Women in their mid-30s would also get coverage for egg freezing – something now only available to women undergoing chemotherapy and other treatments that could compromise fertility. A ban on surrogacy would remain in place.

The bill passed in the French Parliament’s lower house late last month and is slated for discussion in the Senate in the coming weeks.

It won’t become law without a fight, though.

France is often seen as decidedly laissez-faire when it comes to sex and private life. But every so often, the conservative core of what remains a nominally secular but culturally Catholic country erupts.

In 2013, hundreds of thousands took to the streets to protest same-sex marriage. Now, many of the same conservative religious leaders and far-right politicians are urging people to protest the bioethics bill.

“Because it’s unfair to want to authorize the manufacture of children voluntarily deprived of a father,” reads the call to arms of the group organizing Sunday’s demonstrations. “Because this would weaken the familial tissue and thus all of society.”

The head of the French bishops conference suggested Catholics had a duty to protest. The far-right National Rally has said the issue should be put to a referendum.

There is some debate outside the political sphere, as well.

In an official opinion published days before the new bill was debated in Parliament, France’s National Academy of Medicine expressed its support for “recognizing the legitimacy of the desire for maternity in any woman whatever her situation.” But the academy also warned “the deliberate conception of a child deprived of a father is a major anthropological break that is not without risks for the psychological development of the child.”

Olivier Ami, a fertility specialist in Neuilly, an affluent Paris suburb, said in an interview that such concerns are misplaced. He pointed to how many single mothers already exist in France. About 30 percent of his patients have sought reproductive assistance abroad, he said. Spain, Belgium, Britain and the Netherlands are common destinations.

“We can’t forcibly marry all the women who are single mothers – it’s ridiculous,” Ami said.

But while he overwhelmingly welcomes Macron’s revised biothetics law, Ami also voiced reservations about a provision in the bill that would require all potential sperm donors accept that their identities could be one day be disclosed at the child’s request.

When questioned by French lawmakers about this provision, Buzyn, the health minister, said that anonymity probably would survive because couples would not know the identity of their donor and that the donor would never be obligated to meet the child his sperm produced. But lawmakers responded that nothing could conceivably stop a child from one day being able to track down a donor if given his identity.

“We don’t know whether it will be possible to donate anonymously or not,” Ami said. “At the moment we have no idea what will happen.”

Although the debate is heated, political analysts do not expect turnout at Sunday’s rally to rival the anti-gay-marriage protests in 2013, when police said the number of demonstrators reached as high as 340,000 in Paris alone.

“We’re in a new political moment,” said Jérome Fourquet, a political scientist and senior pollster at IFOP, one of France’s leading polling agencies.

Macron, a nominal centrist, has scrambled political allegiances and won over some of France’s practicing Catholics – through his response to the catastrophic Notre Dame fire in April, and by declaring that the nation is “fortified by the engagement of Catholics.”

The Catholic Church also no longer occupies as important a position in the lives of many French citizens, especially among younger generations.

“If this is a political question,” Fourquet said, “it’s also about the evolution of French society, which is leaving, little by little, a certain frame of reference behind.”

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