Having a baby is one of life’s greatest joys and responsibilities. For most couples, conceiving a child is a deeply personal and intimate experience. However, modern reproductive technologies are making it possible for more than two people to contribute biologically to a baby.
What is Three-Parent Baby Technology?
Three-parent baby technology involves using the genetic material from three different individuals to conceive a child. There are two main techniques for creating three-parent babies:
Maternal Spindle Transfer
This technique involves taking the nucleus containing the mother’s chromosomes and implanting it into a donor egg that has had its nucleus removed. The modified egg is then fertilized with the father’s sperm. The resulting embryo ends up with genetic material from three sources: the nuclear DNA from the mother, the mitochondrial DNA from the egg donor, and the sperm DNA from the father.
Pronuclear Transfer
This method is similar to maternal spindle transfer but occurs after fertilization. The pronuclei containing genetic material from the mother and father are removed from a zygote conceived through IVF. These pronuclei are implanted into a donated embryo from which the pronuclei have been removed. This results in an embryo with genetic contributions from three parents.
Why Create Three-Parent Babies?
There are two main medical reasons for pursuing three-parent baby technology:
Preventing Mitochondrial Disease
Defects in mitochondria, the “powerhouses” that generate energy in cells, can cause debilitating or even fatal diseases. Mitochondria have their own DNA separate from nuclear DNA and are inherited maternally. By using a donor egg with healthy mitochondria, genetic diseases caused by mutated mitochondria can be prevented.
Treating Infertility
Implanting the nuclear genetic material from one egg into another woman’s enucleated egg can aid conception in cases of infertility. The donor egg provides healthy mitochondria and other supporting structures to allow fertilization and embryo development.
Ethical Concerns of Three-Parent Babies
While the technology shows promise for preventing disease, the prospect of creating babies with three genetic parents raises some ethical issues, including:
Safety
The long-term health outcomes for three-parent babies are unknown. More research is needed to establish the safety of the techniques.
Identity
Children born this way may struggle with a more complex sense of identity not having a traditional biological mother and father.
Designer Babies
Some fear the technology could lead to genetically modified “designer babies” if used for non-therapeutic purposes.
Commodification
Critics argue three-parent IVF turns babies and women’s eggs into commercial products.
Regulation
Lack of regulation and oversight could promote unsafe or unethical uses of the technology.
Is This Legal?
The legality of three-parent IVF depends on jurisdiction:
- Legal in the UK since 2015 but with tight regulations.
- Legal in Ukraine, Mexico, and parts of the U.S.
- Illegal in Canada, Australia, Japan, China, and other countries.
- A regulatory grey area in many nations.
Has This Been Done in Humans?
Yes, a small number of three-parent babies have been born globally:
- In 2016, a Jordanian couple conceived a son using pronuclear transfer with the help of U.S. and Mexican doctors.
- In 2017, a Ukrainian woman gave birth to a baby boy after undergoing maternal spindle transfer in Ukraine.
- In 2018, a Greek woman gave birth to a girl after getting maternal spindle transfer in Spain and Greece.
The numbers are small because few clinics offer the procedure and strict oversight limits cases.
The Science Behind 3-Parent Babies
Creating three-parent babies relies on several key scientific principles:
Nucleus Swapping
This involves extracting the nucleus of one egg and transferring it into another egg that has had its nucleus removed. This maintains the mother’s nuclear DNA while providing donor cytoplasts.
Spindle Transfer
The spindle apparatus containing the chromosomes can be removed from an egg and transferred into a donor egg. This occurs before fertilization.
Pronuclear Transfer
The male and female pronuclei in a zygote can be transplanted into an enucleated zygote from a donor egg. This happens after fertilization.
Mitochondrial Replacement
These techniques allow for swapping out unhealthy mitochondria inherited from the mother for the healthy mitochondria of a donor, preventing mitochondrial disease.
Assisted Reproductive Technology
IVF is utilized to generate embryos and implant them after performing the genetic modifications through spindle or pronuclear transfer.
Conclusion
The science exists to create human babies with genetic material from three parents, but the practice remains controversial. While it shows promise for preventing serious diseases, more research is needed to establish safety and guard against unethical use. Regulations also need to catch up to the science to find an appropriate balance between benefitting medical science and upholding societal values.
| Technique | Process | Occurs |
|---|---|---|
| Maternal Spindle Transfer | Mother’s nuclear DNA transferred into donor egg | Before fertilization |
| Pronuclear Transfer | Nuclei from mother and father transferred into donor zygote | After fertilization |
This table summarizes and compares the two techniques for creating three-parent babies in terms of the key process involved and whether they occur before or after fertilization.
frequently Asked Questions
Are all 3 parents equally genetically related to the child?
No. The genetic contributions are not equal. The mother provides the majority of genetic material through her nuclear DNA. The father provides half of his DNA through the sperm. The donor usually only contributes mitochondrial DNA, which is just 37 genes compared to 20,000-25,000 genes encoded in the nuclear genome. So the donor parent is minimally related genetically.
Does this mean same-sex couples can have biological children together?
Not exactly. The techniques for making three-parent babies still require an egg from a female and sperm from a male to create the embryo. The egg and sperm provide the majority of the resulting child’s genetic code. However, methods like spindle transfer mean that a woman could use her own egg while having defective mitochondria “replaced” with a donor’s, effectively creating a child with three biological parents. But two people of the same sex could not directly contribute egg and sperm.
Is this the same as cloning?
No. Cloning involves creating an identical genetic copy. Three-parent IVF results in babies with DNA from three people, not copies of any single person. The majority of the child’s DNA comes from the intended mother and father.
Are 3-parent children healthy?
Initial evidence from the few cases so far indicates the children are healthy and develop normally. But the sample size is too small to make definitive conclusions about long-term safety. More monitoring over many years is needed, as well as animal studies to look at multi-generational impacts.
Are there risks to the egg donor?
Egg donation carries the normal risks associated with IVF egg retrieval, including short-term discomfort, hormone treatment side effects, and rare complications like infection or bleeding. In the case of mitochondrial donation, donors take on additional uncertainty given the novelty of the procedures.
Could this lead to “superbabies” with enhanced traits?
In theory it might be possible someday to genetically modify embryos using similar techniques. But experts strongly discourage going down a path to “enhance” designer babies. The techniques currently in use focus on preventing serious medical conditions, not enhancement.
Conclusion
The intersection of cutting-edge reproductive science and ancient human desires to overcome infertility or disability offers both peril and promise. With cautious progress guided by ethics, the medical community aims to harness new technologies like three-parent IVF responsibly. Only through open and thoughtful dialogue will society determine if such innovations ultimately do more harm than good.