Three-parent babies simply explained

three parent babies

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Long time ago when I was still a biology student, no one was interested in mitochondria, or thought they had anything to do with creating healthy eggs and babies.

Twenty years fast forward and I have to explain mitochondria in every second blog post.

What mitochondria have to do with three-parent babies

The United Kingdom Parliament has taken the first step in revolutionizing the field of reproductive endocrinology and fertility by being the first country to allow the creation of what is dubbed “three-parent babies.” This term is catchy, but a bit misleading. Well, quite a bit misleading.

What people should be clearly said is, three-parent baby is simply a term that describes a new, advanced type of in-vitro fertilization (IVF).

Within every cell (eggs included), there is a nucleus that holds over 99% of our DNA. DNA is the genetic code that gives us our inherited traits like appearance, intelligence, and pretty much everything else.

Surrounding the nucleus of the cell is what is called the cytoplasm, a watery substance which functions like the factory of the cell where all the work is done to maintain the cell’s health and function.

Mitochondria are tiny structures present within the cytoplasm, and their primary goal is provide energy to the cell. If mitochondria are mutated or otherwise damaged, they won’t produce CoQ10 efficiently. This will lead to bad eggs, bad embryos, and all kind of infertility issues.

Mitochondria, while still carrying their own DNA (which they posess because once upon a time they were bacteria and lived their own, independent lives), play no part in our inherited traits.

However, when mitochondria do not function properly, they can cause incurable genetic diseases like muscle weakness, deafness, blindness, seizures, cystic fibrosis, organ failure, and even death.

Mitochondrial diseases are passed down by the mother’s malfunctioning mitochondria.

They have no cure and can only be treated symptomatically. That means, in the process of creating a three-parent baby, sick mitochondria will be exchanged for the healthy ones

In the process of creating a three-parent baby, sick mitochondria will be exchanged for the healthy ones.


Process of creating three-parent baby

In this new IVF process, the healthy nucleus of the mother’s egg is transferred into the cytoplasm (which contains healthy mitochondria) of a donor egg that has had it’s own nucleus removed.

This “hybrid” egg is then fertilized with the husband or partner’s sperm, meaning it will have the genetic make-up coming from the mother and the father, plus healthy mithochondria coming from the donor egg.

Simple, right?

The third-party donor’s mitochondria will not play a part in the baby’s personality, physical traits, or talents. Those all come from the nucleus, meaning from the genetic mom and dad.


three parent babies

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This new IVF process with the spectacular name three-parent babies is beneficial for women who have mitochondrial diseases and do not want to risk passing it down to their children.

Three-parent baby prevents the transmission of those inherited diseases that can be debilitating and life-threatening.

Unfortunately, for now, scientists are unable to determine whether or not there will be long-term health issues as a result of using third-party mitochondria.

It should be noted, however, that the studies on human embryos in a lab setting and in monkeys show no evidence of negative effects or characteristics. For everything else, we have no other solution but to wait, as until now there have been too few babies conceived this way.

Why there are no real ethical issues behind the three-parent babies

There are of course skeptics and non-supporters who cite ethical and social concerns like the psychological and emotional impacts on the child in their sense of identity.

While researching for this article, I was surprised how many people discuss three-parent babies and mitochondrial replacement therapy in terms of hurting human dignity?!

But what can give more dignity than enabling someone to be born in a good health and avoid contracting a 100% certain genetic disease?

Some believe, too, that three-parent babies could be the first step to opening the door to creation of “designer babies,” or those with hand-picked positive traits only.

Reading statements like that only makes me wonder: Have people who have such fears ever been in a cell biology lab?  Do they think that work of an embryologist is a cheap science-fiction movie? 

It is of course important to weigh the pros and cons of any type of medical advancement, especially in the area of fertility. However, if three-parent baby prevents serious diseases and turns out to not have any negative long-term side effects, there is no reason to feel anything else but a deep gratitude for this method.

By the way, a very similar technique is currently used in Canada, in the next post I plan to write more about it.

For now, let me just say that my favorite team of scientists at TCART in Toronto use a technology called AUGMENT, where they place healthy CoQ10-producing mitochondria from a woman’s own immature eggs into her mature egg cells to improve egg quality.

In contrary to curing mitochondrial diseases which are extremely rare, AUGMENT has a huge potential to be beneficial for all woman who might be experiencing infertility due to advanced reproductive age or compromised egg quality.

See you soon,



2018-06-18T12:36:32+00:00 April 9th, 2015|Tags: , , |

About the Author:

Darja Wagner, a PhD cell biologist combines her knowledge of cells, hormones and vitamins to help women with infertility issues. She is the author of the blog "All About Egg Health: How to Get Pregnant After 35". Darja helps women to apply latest advances in reproductive biology to maximize egg quality for higher chances of conception, in either a natural way or by means of assisted reproductive technology.