Clones the word just sounds scary even to folks who had the good sense to skip Star Wars Episode II: Attack of the Clones and its scarily dull story filled with cloned troopers.
That's science fiction; the truth is that you may already know a clone, if you know someone who's a twin. And one bioethicist suggests that puts the week's news about scientists cloning human embryos, released by the journal Cell, into a different light.
"Twins. A cloned child would just be a twin," says bioethicist Insoo Hyunof Case Western Reserve University in Cleveland. An identical twin and a clone are essentially the same thing because they have identical genes, he notes. "What would be so bad about having a later-born twin?" Hyun asks.
Even if that's OK, it turns out there's plenty wrong with trying to produce clones in a lab right now, both Hyun and other experts caution.
Identical twins result from a single fertilized egg splitting apart during the early days of pregnancy, leading to two genetically identical embryos growing into twin babies. A clone created in a lab would likewise share the same genes as another person. That person's skin cell chromosomal genes would have to be fused into a donor egg, a process called somatic-cell nuclear transfer. The resultant egg would then be microscopically manipulated to grow into a similar twin embryo to create a cloned embryo that could be implanted into a surrogate mother. Everything but maternal genes left over from the egg would be genetically identical between the skin cell donor and clone.
Fertility clinics already manipulate embryos, uniting eggs and sperm in a petri dish through "in vitro" fertilization, which leads to about 58,000 births a year nationwide. More exotic practices, such as "pre-implantation genetic diagnosis" performed at a few clinics, allow doctors to check IVF embryos for serious genetic defects before implanting them in a mother's womb.
If cloning were safe, Hyun asks, would people be able to tell grieving parents that taking a skin cell from a lost child and fusing its genes with a donor egg to create a twin would be wrong? (There actually was such a case involving a South Carolina couple who funded some cloning research.)
Plenty of people have said it would be wrong, it turns out. The President's Council on Bioethics in 2002, said, "the right to decide 'whether to bear or beget a child' does not include a right to have a child by whatever means," in a critique of cloning to bear children. The Food and Drug Administration explicitly has the power to block such a "therapy" says agency spokesperson Curtis Allen. And the agency has blocked less extreme manipulations of embryos in the past. The International Society for Stem Cell Research opposes "reproductive" cloning, and a statement by national science academies worldwide has called for a ban as well. Veteran stem cell expert George Daley of Children's Hospital Boston said the researchers would see cloning a baby, "not only as unethical, but unsafe and probably illegal."
Safety, it turns out, is the major rub. The human cloning process reported this week would not produce embryos that would lead to a viable pregnancy, says Shoukhrat Mitalipov of Oregon Health & Science University in Beaverton, who headed the Cell report team. A similar process in monkey cells didn't, he says, indicating that the fusing process disrupts the potential for pregnancy, even while it creates embryos that can produce stem cells.
But that doesn't mean someone won't try, which worries stem cell scientist Paul Knoepfler of the University of California-Davis. "Also, with some tinkering, I'm betting someone somewhere is going to get it to work in the next few years, or at least try to do it and fail," he says. That could mean developmentally disabled or otherwise sick babies born, as a result. "I hope I'm wrong," he adds.
Why are some worried? Because most cloning attempts in mammals, more than 90%, end in miscarriages, and many of the ones born alive suffer from severe health defects. "About a third of the cloned calves born alive have died young, and many of them were abnormally large," notes the Energy Department's Human Genome Project office.
I'm not sure about this sh1t. Send in the clones and the bioethicists
That's science fiction; the truth is that you may already know a clone, if you know someone who's a twin. And one bioethicist suggests that puts the week's news about scientists cloning human embryos, released by the journal Cell, into a different light.
"Twins. A cloned child would just be a twin," says bioethicist Insoo Hyunof Case Western Reserve University in Cleveland. An identical twin and a clone are essentially the same thing because they have identical genes, he notes. "What would be so bad about having a later-born twin?" Hyun asks.
Even if that's OK, it turns out there's plenty wrong with trying to produce clones in a lab right now, both Hyun and other experts caution.
Identical twins result from a single fertilized egg splitting apart during the early days of pregnancy, leading to two genetically identical embryos growing into twin babies. A clone created in a lab would likewise share the same genes as another person. That person's skin cell chromosomal genes would have to be fused into a donor egg, a process called somatic-cell nuclear transfer. The resultant egg would then be microscopically manipulated to grow into a similar twin embryo to create a cloned embryo that could be implanted into a surrogate mother. Everything but maternal genes left over from the egg would be genetically identical between the skin cell donor and clone.
Fertility clinics already manipulate embryos, uniting eggs and sperm in a petri dish through "in vitro" fertilization, which leads to about 58,000 births a year nationwide. More exotic practices, such as "pre-implantation genetic diagnosis" performed at a few clinics, allow doctors to check IVF embryos for serious genetic defects before implanting them in a mother's womb.
If cloning were safe, Hyun asks, would people be able to tell grieving parents that taking a skin cell from a lost child and fusing its genes with a donor egg to create a twin would be wrong? (There actually was such a case involving a South Carolina couple who funded some cloning research.)
Plenty of people have said it would be wrong, it turns out. The President's Council on Bioethics in 2002, said, "the right to decide 'whether to bear or beget a child' does not include a right to have a child by whatever means," in a critique of cloning to bear children. The Food and Drug Administration explicitly has the power to block such a "therapy" says agency spokesperson Curtis Allen. And the agency has blocked less extreme manipulations of embryos in the past. The International Society for Stem Cell Research opposes "reproductive" cloning, and a statement by national science academies worldwide has called for a ban as well. Veteran stem cell expert George Daley of Children's Hospital Boston said the researchers would see cloning a baby, "not only as unethical, but unsafe and probably illegal."
Safety, it turns out, is the major rub. The human cloning process reported this week would not produce embryos that would lead to a viable pregnancy, says Shoukhrat Mitalipov of Oregon Health & Science University in Beaverton, who headed the Cell report team. A similar process in monkey cells didn't, he says, indicating that the fusing process disrupts the potential for pregnancy, even while it creates embryos that can produce stem cells.
But that doesn't mean someone won't try, which worries stem cell scientist Paul Knoepfler of the University of California-Davis. "Also, with some tinkering, I'm betting someone somewhere is going to get it to work in the next few years, or at least try to do it and fail," he says. That could mean developmentally disabled or otherwise sick babies born, as a result. "I hope I'm wrong," he adds.
Why are some worried? Because most cloning attempts in mammals, more than 90%, end in miscarriages, and many of the ones born alive suffer from severe health defects. "About a third of the cloned calves born alive have died young, and many of them were abnormally large," notes the Energy Department's Human Genome Project office.
I'm not sure about this sh1t. Send in the clones and the bioethicists
