In paragraph six of this article >
Former Pfizer VP says may cause infertility, petitions against Pfizer/BioNTech Vaccines | Christian Forums
To my understanding, this is talking about how the spike protein is the outer virus structure which attaches a COVID-19 virus to a lung cell, so that then the virus can get into the cell. Therefore, vaccine makers consider it smart to make a vaccine that causes production of antibodies which are specific to go after the spikes on the surface of the COVID-19 viruses . . . so they can't attach to lung cells.
But, if I understand correctly, this paragraph is talking about if there is a specific part of the spike protein which is like to a structural part of a protein which is needed to make the placenta in a pregnant woman. And so, they are saying, an antibody for attacking the spike protein portion can also be specific for attacking a similar part of the placenta protein. And they say this could result in a woman never being able to maintain a placenta for keeping her unborn child.
Now, of course, this might mean women and girls should not get the shot, but I am 73 years old. It could mean I should get the shot so I am not a possible danger to infect younger women and girls.
So, in case a vaccine causes antibodies which are specific for the spike protein plus for similar protein structure in placenta protein, such a vaccine could be an automatic abortion shot . . . I think they mean.
Even so . . . then . . . I am just considering, here > a natural infection will have the COVID-19 virus with its spike protein getting into a person. And these virus spikes, too, could have a portion similar to the protein portion of placenta structural protein . . . possibly. So, if this were the case, a natural virus infection could also cause antibodies hostile to placenta protein.
But > the structure of a vaccine spike could be different than the structure of the spike in a whole virus . . . if the vaccine makers isolate the spike part. So, may be the vaccine spike is different, causing different antibodies than what are produced against it in a natural infection. But in case a natural infection can cause antibodies which also attack placenta protein . . . you might want to wash your hands, wear the mask, and keep the distance.
So, already many unvaccinated people have tested positive for antibodies. I suppose they could radioactively mark their antibodies and see if they show up attached in placental tissue. And this could show if the placenta-similar part of the spike is showing enough to cause an antibody to be made against it, in a natural infection.