Debate began on a bioethics bill in the French Senate Tuesday after tens of thousands of people marched through the streets of Paris to protest state funding for medically assisted procreation for lesbian couples and single women. 

"A child is a gift to be received, not an order to be manufactured. The absence of a father is an injury that can be suffered, but it is monstrous to inflict it on purpose," Archbishop of Paris Michel Aupetit said in a statement ahead of the protest on Sunday.

Critics of the bill have highlighted several bioethical questions surrounding in vitro fertilization, including preimplantation diagnoses, embryo storage, anonymous sperm donation, and the creation of so-called "savior siblings" -- embryos created via in vitro fertilization for the use of the stem cells in their umbilical blood to treat a sick older sibling.

Archbishop Aupetit, who practiced medicine and taught bioethics at a medical school before entering the priesthood, says it is urgent to raise awareness about the potential harmful consequences of this legislation for the most vulnerable.

"For years, we have been committing ourselves ever further to a commercial drift of wealthy countries which afford the luxury of organizing a eugenic trade with the systematic elimination of the most fragile, the creation of transgenic embryos and chimeras," Aupetit said in a statement Jan. 15, issued in French.

Catholic bishops in France have vocally opposed the bioethics bill, the French bishops' conference has compiled statements from 71 bishops on the subject from the last six months. In October, Bishop Jacques Habert of the Diocese of Seez called on French Catholics to pray and fast before the National Assembly discussed the bill.

The conference issued a statement January entitled "No one should treat another as an object," in which the bishops raise concerns as to how the bill prioritizes parents' desire over the good of the child and paves the way for eugenics through preimplantation diagnosis and embryo selection.

"Not only is wanting a child without any genetic variant an illusion, but it would also dehumanize our humanity," the statement reads.

The bill was introduced to the French Senate Jan. 21 after the lower-house National Assembly passed it in October. Debate on the details of the bioethics bill will continue through Feb. 4.

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According to Paris police estimates, on Sunday more than 41,000 people participated in the March for Children in protest of the bill.

Fr. Pierre Amar wrote on Twitter that there was a "massive presence of young people" at the peaceful protest.

In France, IVF is now restricted to men and women who are married or have cohabited for at least two years. Preimplantation diagnosis during IVF treatment is only permitted in cases where one parent is diagnosed with an incurable disease. 

The creation of "savior siblings" -- permitted under a previous bioethics law in 2004 - could be reintroduced to the Senate bill after the National Assembly voted in October to discontinue its use in in vitro fertilization in France.

"We reiterate that every child should be allowed to grow up free and protected in their dignity, in communion with all others, throughout their life, whatever their ethnic or social origin, religion or lack of religion and sexual orientation. No human being can treat another as an object," the bishops said in a joint statement.

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