Science Of A Three-Parent Baby: How Does Mitochondrial Donation Work?

Parenthood is said to be one of the greatest experiences that life has to offer. The mere idea of bringing a new life into the world is quite overwhelming, but the biological process that occurs between fertilization and child birth is fascinating in itself.

With improved technologies at our disposal as a species, numerous couples who were once childless, have also been able to become parents with the aid of improved human knowledge in this domain. As routine as it is, we should cover some of the basics, namely that a child is born of two people of opposite genders, i.e., a male and a female.

But times are changing. What if I told you that a child can now have three biological parents? What if I told you that it has already happened?

Mitochondrial Donation

Before we can fully understand this, we should initially understand in-vitro fertilization (IVF). In-vitro fertilization is a process in which the egg is fertilized by the sperm ‘outside’ the body. Once this egg is fertilized outside, it’s cultured in a growth medium in specific conditions in a laboratory before it is implanted in the woman’s uterus.


Mitochondrial donation is a special type of in-vitro fertilization wherein the baby’s mitochondrial DNA comes from a third party, i.e., someone other than the two parents. This is usually achieved by one of two techniques: cytoplasmic transfer or spindle transfer. As there are three genetic parents involved in the technique, the baby conceived by this process is often called ‘a three-parent baby.’

How Does This Work?

TPIVF or Three Parent In-Vitro Fertilization involves taking out the nucleus of an egg from a female and then inserting it into the cytoplasm (cytoplasm is a thick solution that fills each cell, is enclosed by the cell membrane, and is mainly composed of water, salts, and proteins) of the egg of the other female (the nucleus of this egg is removed prior to this).

the technique

The purpose of removing the nucleus of the second egg is to get rid of any mitochondrial defects in it. Thus, it uses two eggs from different females; the nucleus of one is inserted into the other’s cytoplasm. Although the second egg does have its nucleus removed beforehand, it still contains mitochondrial DNA. This hybridized egg is then fertilized with a male’s sperm. Thus, the baby has identifiable characteristics of three biological parents.


Alana Saarinen was the first girl from the US to be conceived through cytoplasmic transfer and has DNA from three biological parents. Studying her case, scientists have been able to come up with some staggering advantages of TPIVF.

This technique can help in preventing more than 50 genetic conditions. Some of these conditions may subsequently cause blindness, weakness, seizures, deafness, organ failures and even death, so this could be an option for a better life for millions of people.

Alana Saarinen with her parents

Alana Saarinen with her parents

Owing to these benefits seen in real babies born using TPIVF, the United Kingdom became the first country to legalize the process in February 2015, and this will come into force in October 2015. The US is also looking at the matter to make it legal throughout the country.


Although the procedure has seen success in recent years, there have also been many social and ethical controversies surrounding this technique.

Implications on the personality of the child born with this technique have been argued to be detrimental. The child may suffer from psychological and emotional conflicts about its sense of identity. There has been a lot of debate about the effect that mitochondrial donations may have on the emotional wellbeing of the baby.

Critics have also rejected the idea of this technique by saying that humans shouldn’t play ‘God’, as this technique may cause both psychological and physical damages to all three people involved.
There have also been fears that the children born by this technique may be sterile.

Smiling Baby

Photo Credit: DRogatnev/Shutterstock

In the past, when couples were childless, fertility operations appeared as a great relief and changed the lives of millions. Likewise, in the coming years, perhaps we’ll begin to accept this technique too. Let’s wait and see.


  1. Mitochondrial Replacement Therapy – Wikipedia
  2. Unanswered Questions Surround Baby Born To Three Parents – American Association for the Advancement of Science
  3. Cable News Network (CNN)
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About the Author:

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spends a lot of time watching movies, and an awful lot more time discussing them. He likes Harry Potter and the Avengers, and obsesses over how thoroughly Science dictates every aspect of life… in this universe, at least.

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