Can I use my daughter’s eggs so I can have another biological child?
A curious adult from Oklahoma asks:
"I’ve had a hysterectomy but my daughter wants to harvest her eggs for me and my husband so we can have a child of our very own! If I use my daughter’s eggs, can HER father’s DNA be removed from the egg, leaving only my DNA? Then when my husband fertilizes the egg, it’ll be 100% our child together. Is that possible?"
This is a very interesting question! The short answer is no, we do not currently have the technology to remove her father's DNA from the egg cell. It might seem like a straightforward problem, but it's actually more complex than you would think.
You probably know that half of your daughter's DNA came from you and half her DNA came from her dad. This DNA is organized into big structures called chromosomes. So again, half of her chromosomes came from mom and half came from dad.
An egg has only half the usual number of chromosomes. This is so that when a sperm fertilizes an egg, the baby ends up with the right amount of DNA.
So, in a simple world, her egg would have some chromosomes from you and some from her dad. You would need to pluck out the ones that came from her dad and replace them with some from you. Now you would essentially have recreated one of your eggs. This isn't really possible right now with today's technology.
Scientists have found ways to remove a whole chromosome from a cell. Unfortunately, it is very difficult to do this without damaging the cell and egg cells are very delicate.
It is also really hard to pluck the right chromosomes out of your cells and put them back into the egg. All of this means that at this point it is not possible to replace chromosomes in an egg cell.
And even if we could remove a whole chromosome, it still wouldn't be good enough. When a person makes egg (or sperm) cells, their DNA gets shuffled around in a process called recombination.
This means that each chromosome in an egg cell has DNA from both the woman's mom and dad all mixed up together. We certainly don't have the technology to get back to the original chromosome by cutting and pasting chromosomes back together.
DNA is swapped between chromosomes before being put in an egg.
As we mentioned before, your daughter got half her chromosomes from you and half from her dad. When she makes egg cells, a chromosome from you and a chromosome from her dad come together and swap chunks of DNA. This is the process of recombination.
That means that each chromosome in her egg cell has some chunks that are from you and some chunks that are from her dad. Since the chromosomes are all mixed up, we can't remove whole chromosomes to take out her father's DNA.
You might be wondering why the chromosomes swap DNA like that. It's all about variety. If the chromosomes mix themselves up, there can be more genetic variety between people.
Genetic variety is a good thing. It is very important for natural selection and evolution. If a population has a lot of genetic variety, it will be able to adapt to changes in the environment more easily. Plus, variety just makes things more interesting!
Have you ever wondered why the same two people can have six kids that all look different? Part of the reason is that the chromosomes swapped DNA. This means that the same parents can make a lot of different DNA combinations, and even siblings are all genetically unique. Each of their chromosomes is a never before seen mix of DNA.
High Tech Reproduction
These days many people use technology to help them have a baby. Assisted Reproductive Technologies (nicknamed ART) can help people have a baby when they otherwise might not be able to. If your daughter harvested her eggs so that you can have a baby with your husband, this would be a type of ART.
When a woman has a hysterectomy, her uterus is surgically removed. The uterus is the place where a fetus grows during pregnancy. If a woman has had her uterus removed, she will need a surrogate.
A surrogate is another woman who agrees to carry the pregnancy for the couple that is trying to have a baby. There are lots of possibilities with ART and things can get complex!
There are many high tech ways to help parents conceive.
But we haven't reached the point yet where we can change a daughter's eggs back into her mom's. Someday we may be able to take one of your cells and coax it back into an egg using stem cell technology. Then your egg would be fertilized with your husband's sperm.
Although we're not able to change the DNA inside of egg cells at this point, there are lots of ways that technology can help people have children. Families form in lots of different ways and luckily there is a lot more to a family than just shared DNA!
Author: Reana Tischler
When this answer was published in 2011, Reana was a student in the Stanford MS Program in Human Genetics and Genetic Counseling. Reana wrote this answer while participating in the Stanford at The Tech program.