A US Senator on Friday sent a letter to her colleagues urging them to vote against the confirmation of Amy Coney Barrett to the Supreme Court because of her association with a group that holds in vitro fertilization to be morally illicit.

"Barrett's willingness to associate her name with such an organization is disqualifying and, frankly, insulting to every parent, hopeful parent or would-be parent who has struggled to start a family. Formally signing on to the message of an organization with these radical views goes beyond other nominees and demonstrates a lack of judgment, an absence of due diligence and a derision toward families like mine who were only able to have children with the help of methods and assistance that Judge Barrett personally disapproves of," Sen. Tammy Duckworth (D-Ill.) wrote Oct. 2.

In 2006 Barrett signed an ad placed by St. Joseph County Right to Life in the South Bend Tribune. The signatories said they "oppose abortion on demand and defend the right to life from fertilization to natural death."

Duckworth asserted that because of this, Barrett "likely doesn't believe my little Maile and my growing Abigail should have ever been born in the first place."

Both Duckworth's children were conceived through IVF.

The senator wrote: "I urge you to fully consider the message a vote in favor of a Supreme Court nominee who appears to believe that my daughters shouldn't even exist sends not only to me as a mother and as your colleague, but to parents-to-be around this country struggling with infertility and whose dreams may only be achieved through IVF or other technologies."

She said that Barrett's "willingness to associate her name" with St. Joseph County Right to Life "is disqualifying and, frankly, insulting to every parent, hopeful parent or would-be parent who has struggled to start a family."

"Formally signing on to the message of an organization with these radical views goes beyond other nominees and demonstrates a lack of judgment, an absence of due diligence and a derision toward families like mine who were only able to have children with the help of methods and assistance that Judge Barrett personally disapproves of," Duckworth continued.

She added that she fears that as a Supreme Court justice, "Barrett would be unable to resist the temptation of overturning decades of judicial precedent in an effort to force every American family to adhere to her individual moral code. I fear that if a case involving ART were to be brought before the bench, families like mine would not be able to trust that her opinions would be based on facts, laws and the Constitution rather than swayed by her personal beliefs."

The Catholic Church teaches that though IVF is morally illicit, "every child which comes into the world must in any case be accepted as a living gift of the divine Goodness."

In Dignitas personae, its 2008 instruction on certain bioethical questions, the Congregation for the Doctrine of the Faith noted that IVF "very frequently involves the deliberate destruction of embryos" and that "all techniques of in vitro fertilization proceed as if the human embryo were simply a mass of cells to be used, selected and discarded."

"The blithe acceptance of the enormous number of abortions involved in the process of in vitro fertilization vividly illustrates how the replacement of the conjugal act by a technical procedure – in addition to being in contradiction with the respect that is due to procreation as something that cannot be reduced to mere reproduction – leads to a weakening of the respect owed to every human being," the congregation taught.

"The Church recognizes the legitimacy of the desire for a child and understands the suffering of couples struggling with problems of fertility. Such a desire, however, should not override the dignity of every human life to the point of absolute supremacy. The desire for a child cannot justify the 'production' of offspring, just as the desire not to have a child cannot justify the abandonment or destruction of a child once he or she has been conceived."

The instruction added that "in order to come to the aid of the many infertile couples who want to have children, adoption should be encouraged, promoted and facilitated by appropriate legislation so that the many children who lack parents may receive a home that will contribute to their human development. In addition, research and investment directed at the prevention of sterility deserve encouragement."

And in Donum vitae, a 1987 instruction on respect for human life in its origin, the congregation affirmed that "although the manner in which human conception is achieved with IVF and [embryo transfer] cannot be approved, every child which comes into the world must in any case be accepted as a living gift of the divine Goodness and must be brought up with love."

Barrett and her husband have seven children, two of whom were adopted from Haiti.

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Barrett was nominated to the Supreme Court Sept. 26.

Her Senate confirmation hearing and a vote on her nomination are expected to take place at the end of October, shortly before the Nov. 3 presidential election.

Barrett previously came to national attention during her 2017 Senate confirmation hearings after she was nominated by the president for the U.S. Court of Appeals. During that process, Sen. Dianne Feinstein (D-CA) stated that "the dogma lives loudly" within Barrett, and "that's a concern."

During those hearings Barrett insisted that as a judge, she would honor binding precedents, and would not let her religious beliefs inappropriately alter her judicial decisions.

Asked by Sen. Dick Durbin (D-Ill.) about how she would rule on a case involving same-sex marriage, Barrett stated: "From beginning to end, in every case, my obligation as a judge would be to apply the rule of law, and the case that you mentioned would be applying Obergefell, and I would have no problem adhering to it."

Criticism of Barrett is part of a "virus" of anti-Catholic "bigotry," Archbishop Charles Chaput wrote last week at First Things.

"It seems to infect a number of Democratic senators, including Sen. Kamala Harris, Feinstein's California colleague and vice presidential nominee, who saw looming peril in that dangerous national conspiracy otherwise known as the Knights of Columbus."

The emeritus Archbishop of Philadelphia warned that public attacks on the Supreme Court nominee's faith constitute a wider threat to religious liberty.

Archbishop Chaput said that "those who value our First Amendment right to religious freedom should realize that tests about belief are attacks on religious liberty."

In her letter, Duckworth had written that "while we are each, of course, entitled to our own beliefs about women's access to constitutionally-protected healthcare choices," St. Joseph County Right to Life's views are "radical".

The archbishop stated that "positioning dissenting Catholics as 'mainstream Americans' and believing Catholics as 'extremists'" is now a "common and thoroughly dishonest culture war technique," and "a particular affront to the free exercise of religion."