The experimental drug US President Donald Trump credited with beating his COVID-19 infection was tested with the help of a cell line originally derived from an aborted fetus.
The Trump administration has notably opposed medical research that uses fetal tissue from elective abortions, while knocking back numerous requests from scientists to work with it.
Last Friday, Mr Trump tweeted confirming he and First Lady Melania Trump had tested positive for COVID-19.
The president was administered Regeneron Pharmaceuticals's REGN-COV2, which is an experimental and unapproved antibody cocktail used to treat COVID-19.
Mr Trump went on, and also said the drugs he had been given were like "miracles coming down from God".
Regeneron's antibody cocktail was, in early stages, tested on a common cell culture called HEK 293 - a line of cells originally derived from an aborted fetus in the Netherlands in 1973.
The antibodies given to Mr Trump were not made from fetal tissue, but similar antibodies were, at an earlier stage, tested on a cell line originally derived from an aborted fetus.
In a statement on the research in April, the pharmaceutical company said: “Regeneron uses a wide variety of research tools and technologies to help discover and develop new therapeutics. Stem cells are one such tool.”
It noted there are “limited research efforts employing… human embryonic stem cells".
The use of HEK-293 cell lines is common practice in medical research.
In 2019, the Trump administration imposed restrictions on the federal funding of research requiring fetal tissue.
In March this year, a senior immunologist at the National Institutes of Health , arguing that the pandemic warranted an exemption. The requests were denied.
Under the Trump administration's new rules, scientists must detail exactly why they require fetal tissue and how much of it will be obtained.
Regeneron, in a statement, said the cells used are “approved for research use by the National Institutes of Health” and “adhere to federal and state laws and regulations”.
Mr Trump has also said he wants to overturn federal protections for abortion rights.
His campaign also boasted that in his first week in office, the president reinstated and expanded the Mexico City Policy that prevented $US12 billion in aid being used to fund non-governmental abortion services.
Even amid his recovery, Mr Trump tweeted about being "pro life".
The testing of coronavirus vaccines on the HEK-293 cell line has proven controversial in Australia too.
In August, Catholic Archbishop of Sydney Anthony Fisher, Anglican Archbishop of Sydney Glenn Davies, and Greek Orthodox Archbishop Makarios wrote to Prime Minister Scott Morrison raising ethical doubts about the Oxford University coronavirus vaccine, which has been tested using the same HEK-293 cell line.
They argued the harvesting of fetal tissue was "deeply immoral" and warned members of their leaders' congregations may decide to refuse the vaccine.
The issue has divided the country's faith leaders, with Jewish, Hindu and Islamic leaders.
