(Whew. If you haven't watched Doctor Who, I imagine this is going to sound super silly. If you haven't watched it and intend to, then what are you waiting for? Spoiler alert, in that case. But I'm not going to let it stop me because this episode aired in 2006. You've had eight years.)
The Doctor and Rose visit a hospital in New New York, which is staffed by what Wikipedia describes as "humanoid feline nurses" called the Sisters of Plenitude. The Doctor is astounded by the medical advances that have been made by the Sisters, as they have cured diseases that he knows not to have been cured for a while yet.
A lot goes on, as episodes of DW tend to go a bit manic sometimes, but it is revealed that the Sisters of Plenitude have been making their medical advances by breeding humans, intentionally infecting them, and then figuring out how to cure the diseases. When the Doctor finds out, he says of the patients, "They were born sick, they're meant to be sick. They exist to be sick: lab rats. No wonder the Sisters have got a cure for everything, they've built the ultimate research laboratory, a human farm."
One of the Sisters, Novice Hame, says by way of justification, "It's for the greater cause... They're not real people, they're specially grown. They have no proper existence." Furthermore, all they are is "flesh," and thousands of people are alive thanks to the cures developed using this method.
The Doctor is not having this: "These people are alive. If [the humans outside the hospital] live because of this, then life is worthless."
Every time I've seen this episode -- which is a lot, I'm kind of a Doctor Who junkie -- it has struck me anew that whether the producers meant it or not, this is a powerfully pro-life episode. How is the crime of the Sisters of Plenitude meaningfully different from fetal stem-cell research? Human embryos are harvested for medical research, and it is justified with the argument that it's all for the greater good, and that the quality of life is improved for "real" people, at the expense of farmed flesh which isn't really a person.
But that embryo is a person.
The bred humans of New Earth are regular humans who would lead regular human lives if given the chance. So too, embryos grow into fetuses (otherwise known as "babies"), which are born and grow into toddlers, children, tweens, teens, and eventually adults. Regular human adults who live regular human lives if given the chance. At no time during the development from fertilized ovum to adult is a person anything other than a person, and people are not test subjects (unless they give informed consent, as with legitimate medical trials).
Those harvested embryos are test subjects, stripped of their humanity except for what that humanity can do for our health.
And if we live because of this, then life is worthless.