Genetic Contribution Does Not Make a Parent
A truth known to parents through adoption is closer to being realized by parents through assisted reproduction: Genetic contribution does not make a parent.
A recent scientific breakthrough was covered widely by the media (1) where three adults contributed genetics to a single child: Cellular DNA from the sperm of one parent, cellular DNA from the egg of another parent, and mitochondrial DNA from a donor egg. So, if we consider ‘parents’ being those people who contribute genetics to their child, each of these children would have three different ‘parents.’
Of course, the true intended parents are those who want and care for the child, and it has nothing to do with how much or what type of DNA they offer. However, this breakthrough not only allows those with potentially lethal defects in their mitochondrial DNA to have children, but also it makes it more acceptable for my husband and me - and all gay intended parents - to be more equally recognized as parents to our children born through in vitro fertilization (IVF) and surrogacy.
What is Mitochondrial DNA?
Anyone who has ever gone to an elementary school science class remembers one thing about mitochondria (say it with me now): Mitochondria are the powerhouse of the cell.
The reason these powerhouses are such a special organelle is because of their unique history and evolution. Mitochondria were actually once bacteria cells that were engulfed by eukaryotic cells, which means that they - like all single cell organisms - possess their own genetic coding or DNA.
(2)
Mitochondria DNA (mtDNA) codes for 13 proteins or subunits of the complex oxidative phosphorylation system. This is the system that creates cellular energy and makes the mitochondria the ‘powerhouse’ we all know and love.
While sperm have a handful of mitochondria in order to power the flagella and allow for movement, these are destroyed during fertilization. The egg, however, contains on average about 200,000 mtDNA molecules, and these are the sole contributor to the child’s future mitochondrial reserves.
Given that mitochondria and their DNA are responsible for providing all the energy our bodies need to run, defects can be catastrophic. Mutations in mtDNA can lead to a number of illnesses ranging from exercise intolerance to Kearns–Sayre syndrome (KSS), which causes a person to lose full function of heart, eye, and muscle movements (2).
Prior to this recent breakthrough, women who had certain mtDNA defects could not reproduce biologically, for fear of passing their mutations on to their children. However, this new method allows the donation of mitochondria, allowing these women to contribute cellular DNA but not mtDNA to their children.
How Does the Science Work?
The research has been published in the New England Journal of Medicine (NEJM) (3), and the science is like something out of a science fiction novel.
(3)
The image above is from the NEJM publication and provides a simplified overview of the lab procedure.
The donor (blue) will contribute the mtDNA. The patient (orange) will contribute the cellular DNA, and this row of the image represents the intended parents (sperm+egg cellular DNA).
Intracytoplasmic sperm injection (ICSI) is performed on the donor and patient egg to make two fertilized embryos. For a review on ICSI, check out this previous Gay Dad Reporter article.
After fertilization, both embryos are ‘paused’ in their development using cytoskeletal inhibitors to prevent further cellular division.
The cellular DNA from each of the embryos is removed, and the cellular DNA from the intended parents is placed into the enucleated (AKA nucleus removed) embryo with the donor mtDNA.
The embryo is then allowed to continue to develop with the cellular DNA of the patients (intended parents) and the mtDNA from the donor.
Finally, the embryo undergoes preimplantation genetic testing (PGT) in order to test for abnormalities before being implanted into the intended mother or gestational carrier (GC).
The intricacy of this genetic and cellular manipulation is beyond impressive, and the results of the study are equally notable. Of the 8 live births that resulted from this procedure, levels of the maternal abnormal mtDNA variant were 95 to 100% lower in 6 newborns and 77 to 88% lower in 2 newborns than in the corresponding enucleated zygotes. While the procedure is not always 100% in removing all the patient’s mtDNA, these replacement levels of at least 77% mean that these children are not likely to develop any severe defects as a result of mutations in their mtDNA. They are effectively ‘cured,’ and if the children are female, they will be at little to no risk of transferring mutated mtDNA to their own children, which means that the genetic risk has been removed from the family and gene pool.
What Does this Mean for Gay Intended Parents?
While this is incredible science in and of itself, for the purposes of the Gay Dad Reporter, I believe this is also socially impactful for gay intended and current parents.
For gay dads, there is always the annoyingly ignorant question, often from complete strangers, that goes something like: ‘But who is the REAL dad?’
The person asking this obviously wants to know who contributed the sperm to the child, but in asking this, they are insulting both fathers, the child, and anyone who is a parent without contributing DNA.
This is not a debate about nature versus nurture. I am not saying that genetics do not contribute to how a person will look, behave, or who they will become. That is not disputable. What I am saying is that being a parent is all about intention. You have to want to be a parent in order to be one. That is what matters.
This breakthrough makes that even more apparent because there is a 3rd genetic contributor to these children who is a donor and no way a parent. They have donated their mitochondria, and that is it. I believe this can also help evolve how the outside world sees the egg donor for gay fathers. The woman who donates her eggs is incredible and an essential part of the procedure that allows myself or any other gay man to become a parent through surrogacy, but she is not a parent. She should not be viewed that way, just like the mtDNA donor is not a parent. Just like everyone who contributes DNA only and no intention to parent is not a parent.
I started this article saying that parents through adoption already know what makes a parent. Now parents through IVF and surrogacy can have even more confidence that both parents are equal and should be viewed as such by themselves and the outside world. Gay dads are both dads, and there is no mother. There is a genetic contribution from an egg, but she is not a mother, just like the mtDNA donor is not a mother. The mother - if there is one or maybe two - is the woman who wants to be the mother and cares for the child.
In the future, procedures like in vitro gametogenesis (IVG) are likely to remove the need for egg donation in order for gay men to have children. Our children will be genetically from us the same way as children from a straight couple. However, future scientific exploration could also mean that we will have the ability to build a genetic composition from both parents, taking pieces of each genome and hybridizing them to allow for unique parts from both parents (and donors) to be selected for their children.
While this opens a huge door for ethical challenges, ‘designer babies,’ and other social considerations that we will have to deal with, the truth remains that the future will allow us this type of precision reproduction. We will have to deal with it, but on the plus side, it will mean that gay, straight or any type of family through assisted reproduction will be viewed as parents and their child, regardless of where their genetics or cellular powerhouses come from.
No one will ask who the ‘REAL’ dad, mom, or parent is. Every parent will be a real parent.
It’s a brave new world, and one that I am excited to see develop for my own and other rainbow families.
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