It would take many years and dozens of papers before ovarian stem cell research could be included in medical textbooks. They are still controversial. (Some of these papers contained conflicting data, and some scientists are still skeptical.
At some level, the hostility to the possible existence of ovarian stem cells isn’t surprising. Science is prone to resist new information being destabilized, at least initially. Neuroscience took many years to accept that brain cells can regenerate in humans, despite evidence from other species. Today the finding that neurons die and are replaced throughout life is recognized as one of biology’s greatest paradigm shifts, inspiring new possibilities for tackling degenerative conditions like Parkinson’s and Alzheimer’s.
The idea that neurons can regenerate was resisted partly because of deeply held ideas about human exceptionalism. Some argued that the mere fact that songbird neurons can regenerate tells us very little about the brain of a sophisticated human. It was believed that humans were special. Humans were not birds.
In the case the ovary, it may be that there is another factor: deeply held beliefs about the differences in men and women.
“Cultural biases about women” have long shaped Evelyn Telfer, a University of Edinburgh reproductive biologist, stated that reproductive medicine and science are two different things. She has been studying ovaries since 1980s and led a study suggesting the possibility that the human ovary could be capable of producing new eggs in adulthood. And these biases, “whether conscious or not,” are likely shaping responses to ovarian stem cell research, too, she said.
Biology texts describe men to be reproductively prolific. They continue to make sperm into old age, producing hundreds of sperm for every breath they take. Their quality is another matter. By contrast, ovaries are said to “fail” (despite the fact that they continue to make some hormones after menopause). “The field was so entrenched in the idea that the ovary had no regenerative capacity, period,” said Dr. Tilly. “It came out of decades of the unfailing belief that the ovary was different from the testis.”
How can we explain menopause if the ovaries are able to regenerate? Traditionally, it’s been defined as simply running out of eggs and ceasing to menstruate — the hourglass metaphor. Ovarian stem cell research suggests an alternative possibility. Perhaps it isn’t that ovaries run out of eggs but that the cells that nourish those eggs and pump out hormones to the rest of the body may be too damaged to continue. (This idea is supported in part by the fact that stem cells were found in the ovaries postmenopausal woman.
Source: NY Times
