TV Review: DNA Family Secrets – Series two, episode three

How would you feel not knowing your parents' real identity? How would you feel knowing your biological father could be a murderer? For some, these are not hypothetical scenarios, so they turn to DNA testing to find out their ancestry.

The BBC documentary, DNA Family Secrets, is centred around the unordinary stories of ordinary people to reveal the immense power of DNA testing, which can answer various questions about one's identity and health. However, as a scientist, I felt that the episode lacks important details about the science behind DNA sequencing and its accessibility, which would be of interest to the general public.

Episode three of series two tells the story of a donor-conceived woman, Mel, trying to find her biological father and potential family members using a DNA test. She is one of 6000 babies born in the 1970s in the UK using donor sperm. Back in those days, sperm donation was not regulated and records about donor identity were very limited to ensure donor anonymity. Women were even advised by doctors to keep it a secret from their donor-conceived children. However, recent advances in DNA technology, which were not specifically mentioned, have been used by many donor-conceived or adopted individuals to trace their biological parents.

Professor Turi King from the University of Leicester explains to Mel that matching DNA to relatives relies on a big public database containing the DNA information for 30 million people and that there is no guarantee Mel will find out who her biological father is. Finding out who her biological father is had been on her mind since she was a teenager, when her mother told her the truth about the anonymous sperm donor she used to get pregnant. Mel is simply relying on a DNA test to find out who that man was. Even the slightest piece of information would put her mind to ease as now every stranger on the street could be the sperm donor she is looking for.

The episode does not delve into the specifics of DNA testing: how it is performed, its advantages or disadvantages. It is also intriguing to understand what kind of information the public DNA database can give you, which unfortunately is not named. Professor King only briefly mentions that Mel shares 50 percent of her DNA with her biological father, and a quarter with any potential siblings. Two months after Mel has provided a sample for a DNA test, DNA matches from her biological father's relatives are used to build a family tree to reveal her father's identity. Although it is discovered Mel's father has passed away, DNA testing revealed other close relatives. Her half-brother appears and tells the story of their biological father who had probably volunteered to donate his sperm after an appeal in the 1970s. The power of knowing her real identity brings Mel the closure she deserves after so many years of unknown.

Next, the documentary tells the story of Fi, who was adopted after birth and is looking to find out if her biological father was a murderer. When 20 years old, she traced her biological parents and discovered that her mother was killed by Fi's supposed biological father.

Fi has been worried that if her father was inclined to violence she is capable of acting the same way. Professor King emphasised that one doesn't know what they inherit when they are adopted. However, she affirms that our genetics do not solely determine how we act, and that environment also has an input. After a DNA test, Fi finds out there was no overlap between the biological tree of her father and the man on her birth certificate.

DNA testing also gives us more knowledge and power over our lives regarding inherited diseases. It can reveal DNA mutations associated with cancer development and many more.

The episode also features the story of Bahaa, who wants to find out if he carries a cancerous mutation like his brother. A mutation in his brother's genes led to Lynch syndrome. This DNA change predisposed him to bowel cancer, which was treated with a life-saving surgery and chemotherapy. There is a 50 percent chance Bahaa has inherited the same mutation. After a simple DNA test and a month's wait, Bahaa receives the happy news that he is not a carrier. This also means his children did not inherit the mutation, a relief for the father of two.

The power of a DNA test can unlock life-changing secrets because DNA does not lie; it reveals the truth about our past, but also the future. Thinking you can reveal the identity of your biological parents could give you the opportunity to know your own identity, especially as donor anonymity becomes harder to protect due to the rise of direct-to-consumer genetic testing. However, I think the happy end in all three stories gives a false perspective about how scientists can answer any question on donor identity and inheriting genetic diseases. The documentary does not discuss the science behind DNA testing or the complex nature of data protection and sharing DNA information. It leaves the viewers with the question: is it possible for anyone to trace their family tree and get answers about their health, and at what price?