The controversial videos surrounding Planned Parenthood has brought to light issues on fetal tissue research and donation.

For decades, scientists have, in fact, been using fetal tissues for various medical experiments and while this is not usually discussed outright, this has helped advance studies for diabetes, eye disease and muscular dystrophy, according to The New York Times.

Research into fetal tissue use started in the hopes of developing a vaccine for polio in the 1930s, according to the American Society for Cell Biology and in recent years, the studies have been instrumental in finding treatment for Parkinson's disease.

Today, research on fetal tissue is being undertaken in the study of AIDS and the advancement of stem cell research, which is still in its infancy stages. "Think of fetal tissue as a kind of instruction booklet," said Sheldon Miller of the National Eye Institute in The NY Times.

Researchers take tissue samples from an aborted or miscarried fetus and then grow cells from this inside Petri dishes. These tissues come from abortion clinics or hospitals, and the process of obtaining and distributing these are handled by non-profit organizations, such as Planned Parenthood, to supply the researchers.

There are guidelines that must be followed, according to the U.S. Department of Health and Human Services. The guidelines were set in 1993.

In some cases, expenses for processing, transfer and storage of the fetal tissue are reimbursed to the companies or organizations that supply the fetal tissue, and these are apparently reasonable, legal expenses. "It appears to be legal, no matter how much you charge," said Arthur Caplan of NYU Langone Medical Center, according to The NY Times. "It's a very gray and musty area as to what you can charge."

"Reasonable expenses" also appears in the American Medical Association Code of Ethics, which states that "fetal tissue is not provided in exchange for financial remuneration above that which is necessary to cover reasonable expenses."

These guidelines also dictate that a woman who has undergone abortion must give her full consent to donate the fetal tissue, and the matter must only be discussed only after she has had the procedure. The reason for this is simple: to prevent women from getting more abortions just to donate fetal tissues.

But for many anti-abortionists, there is no gray area in this matter. "It makes Planned Parenthood or any abortion clinic look like it's trying to generate some other source of income, and it puts the clinic in a position that generates a lot of unease," Caplan offered an explanation in separate interview with Vox.

"For critics of abortion, the idea of making something good from something they see as inherently evil is not something they have room for," he further said.

At this point, two video exposés on Planned Parenthood's involvement in fetal tissue research have already been released by the Center for Medical Progress, the anti-abortion group. Following this, the Senate will vote on whether to defund the organization by Aug. 3, according to The Hill.