Creating Sperm From Stem Cells Raises Ethical Concerns: Making Males Redundant?
July 9, 2009 - 4:52 AM<br />
The bizarre plotline of The Baby Formula may not be quite as outlandish it is sounds. Researchers at Newcastle University in Britain announced this week that they had succeeded in creating human sperm from embryonic stem cells.
The team led by Prof. Karim Nayernia said the “in-vitro designed” (IVD) sperm appeared fully functional although their “full potential … remains to be demonstrated.”
The difference between the researchers’ accomplishment – published Wednesday in the journal Stem Cells and Development – and the one depicted in the movie, however, is a significant one:
Nayernia’s team was able to produce IVD sperm from stem cells with male (XY) chromosomes. When it tried to do so with female (XX) chromosomes they were prompted to form early-stage sperm, but failed to progress further.
“This demonstrates to researchers that the genes on a Y chromosome are essential for meiosis and for sperm maturation,” they said in a statement.
The researchers described the development as one that would lead to “a better understanding of the causes of infertility.” They stressed that they will not use the IVD sperm to fertilize eggs and implant the resulting embryos in a woman’s womb.
“While we can understand that some people may have concerns, this does not mean that humans can be produced ‘in a dish’ and we have no intention of doing this,” Nayernia said.
“This work is a way of investigating why some people are infertile and the reasons behind it. If we have a better understanding of what’s going on, it could lead to new ways of treating infertility.”
But while the Newcastle research team may not plan to proceed down that path – British law currently bans fertility treatment using sperm or eggs made in a laboratory – others may attempt to do so in the future.
And while creating sperm from female stem cells may be doable, Nayernia for now is on record as saying that it is possible, in principle.
There also is the issue of safety: In earlier work, Nayernia in 2006 used ESCs to create sperm which was then used to fertilize female mice. Seven live baby mice were produced but, according to the researcher, they “apparently had growth abnormalities and died within 5 months after birth.”
News of the latest development is troubling to some ethicists.
“If scientists can now manufacture sperm, that simply makes males even more redundant than they already are,” Christian commentator Bill Muehlenberg of the Australian Family Council of Victoria, said Thursday.
“This is really parthenogenesis, or procreation by one sex alone. This might be good for amoebas, but it is not good for human beings, and certainly not good for the children who come about by such a process.”
Muehlenberg also pointed to another major ethical concern – the use in scientific research of stem cells from human embryos, which are destroyed in the process.
Dr. David van Gend, national director of Australians for Ethical Stem Cell Research, said the news took the exploitation of embryos to “a sinister new low.”
“This is an abuse both because of its implications – namely, that scientists can now exploit a dead embryo as a source of sperm – but also because it was entirely unnecessary to use embryos as the source of stem cells,” he said in a statement.
Van Gend pointed to a relatively new discovery in stem cells science which proponents say has made the controversial use of embryonic stem cells (ESCs) – whether donated after IVF treatment, or cloned in a laboratory – unnecessary.
In late 2007, Japanese and U.S. scientists reported that ordinary human skin cells can be reprogrammed into a new kind of cell – an induced pluripotent stem (iPS) cell – that shares an embryonic cell’s potential to develop into other types of cell such as blood, brain and muscle.
Because iPS cells genetically match the person whose skin cells were originally used, the risk of rejection by the patient’s immune system when those cells were used in therapeutic treatments was minimized.
“We know that iPS cells, derived from adult cells without ever using eggs or embryos, are the exact functional equivalent of ESCs,” van Gend said. “Anything an ESC can do, an iPS can do – with the further advantage that iPS exactly matches the patient.”
“The sperm created from embryos are that embryo’s sperm,” he noted. “The sperm created from an iPS cell are the sperm of the adult whose skin cell was transformed into an iPS cell, and then into sperm.”
Van Gend acknowledged that there may be medical value in learning how to create sperm from stem cells, such as enabling men who have become infertile as a result of childhood mumps or cancer treatment to regenerate their own sperm, from their own cells.
“When this is done with iPS cells from the man himself, that avoids the exploitation of an embryo, and keeps the relationship of father-mother-child intact, since the sperm cells would indeed be derived to the patient himself,” he said.