Moreover, embryos whose parents do not sign the necessary paperwork to allow the embryos to be used for research remain "stuck."
The Catholic Church stresses that all human persons – including those in the embryonic state – have an invaluable human dignity.
In 1998, the U.S. bishops' conference published a document explaining that "the Church has clearly and unequivocally judged [IVF] to be immoral."
In the 2008 instruction Dignitatis personae, the Congregation for the Doctrine of the Faith noted that the typical uses for already frozen embryos- the treatment of diseases, treatment for infertility, and even "prenatal adoption"- all present ethical challenges and leave the embryos "susceptible to further offense and manipulation."
"The practice of multiple embryo transfer implies a purely utilitarian treatment of embryos," the congregation wrote.
"One is struck by the fact that, in any other area of medicine, ordinary professional ethics and the healthcare authorities themselves would never allow a medical procedure which involved such a high number of failures and fatalities...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 Congregation also quoted a 1996 address by Pope St. John Paul II in which he made an "appeal to the conscience of the world's scientific authorities and in particular to doctors, that the production of human embryos be halted, taking into account that there seems to be no morally licit solution regarding the human destiny of the thousands and thousands of 'frozen' embryos which are and remain the subjects of essential rights and should therefore be protected by law as human persons."
Pope Francis has said that there is no outcome that can justify the use or destruction of embryos for scientific purposes – including research aimed at curing diseases.
"Some branches of research, in fact, utilize human embryos, inevitably causing their destruction. But we know that no ends, even noble in themselves, such as a predicted utility for science, for other human beings or for society, can justify the destruction of human embryos," he said during his general audience May 18.