The story behind the interaction of fetal cell lines and the COVID vaccine is more complex than either side is owning

The science for how the mRNA development differs from the J&J vaccine: 

https://www.nebraskamed.com/COVID/you-asked-we-answered-do-the-covid-19-vaccines-contain-aborted-fetal-cells

https://www.nationalgeographic.com/science/article/here-are-the-facts-about-fetal-cell-lines-and-covid-19-vaccines

Snopes on the veracity of the claim

https://www.snopes.com/fact-check/covid-vaccine-aborted-fetal-cells/

The debate on the tradeoffs

https://www.usccb.org/news/2021/us-bishop-chairmen-doctrine-and-pro-life-address-use-johnson-johnson-covid-19-vaccine

https://www.kark.com/news/health/coronavirus/arkansas-hospital-lets-staff-seek-vaccine-exemption-as-long-as-they-dont-use-other-meds-tested-on-fetal-cell-lines/ (but see next blog article on why that's not quite right)

https://stream.org/yes-you-can-morally-object-to-a-covid-vax-and-still-take-aspirin/ (doesn't say which of the four on the list were tested during their development)

https://www.patheos.com/blogs/throughcatholiclenses/2021/01/if-any-drug-tested-on-hek-293-is-immoral-goodbye-modern-medicine/

https://churchlifejournal.nd.edu/articles/you-can-have-your-tylenol-too-a-note-on-the-objections-of-some-catholics-to-using-covid-19-vaccines/ (counter argument that post-development testing really isn't that different)

https://churchlifejournal.nd.edu/articles/does-the-origin-of-the-cell-lines-used-to-test-covid19-vaccines-make-any-difference/