DNA profiling has been available for over 40 years, thanks to techniques developed by Sir Alec Jeffreys in 1984. By 1988, DNA fingerprinting was available for paternity testing (Adams, 2008).
However, before the availability of modern-day DNA testing, people would look at different traits, such as blood type, physical resemblance, and behaviour to determine the paternity of a child.
In this blog, we look at some of the ways people try to determine paternity without a DNA test – and why DNA testing is the only 100% accurate, reliable way of establishing paternity.
Blood type analysis
Even though we inherit our blood type from our parents, comparing a child’s blood type with that of the alleged father is not a reliable way to determine paternity.
According to the NHS Blood Donation website, approximately 35% of the UK is O positive. That translates to roughly 23 million people in the UK!
As so many people have the same blood type, it is impossible to ascertain the true biological father of a child by comparing blood types alone.
Inherited traits
When we talk about inheritance in biology, we mean genetic traits that are ‘passed down’ from parent to child. Characteristics such as eye colour, vision problems, and even genetic conditions are inherited from our parents.
The problem with attempting to verify paternity by comparing such traits is that they are complex and therefore not at all reliable for confirming paternity.
For example, although it was previously assumed that inheriting eye colour was as simple as inheriting your blood group, there are roughly 16 different genes associated with the determination of eye colour.
Therefore, it is not possible to determine paternity by comparing the eye colour of the alleged father with that of the child.
There are also many different genes involved in inherited traits such as genetic disorders. If a genetic condition appears in a child when no one else in the family appears to have it, or if a condition is not present in a child when many people in the family have it, it might raise questions in people’s minds about the child’s paternity.
However, without knowing which genes are involved and who is affected or unaffected, it is not possible to accurately determine paternity, without the use of a DNA test.
Behavioural traits/personal preferences
Much like our ability to lose or gain weight, genetics can impact our behavioural traits or personal preferences to a degree.
For example, multiple people in the same family might be musically or artistically gifted. However, this does not mean that anyone in the family who does not share this talent is not biologically related.
Our environment plays a big part in shaping who we are, what we are interested in, our talents etc.
The genetic and environmental factors that influence our behaviours are vast and complex, and it is therefore not possible to determine paternity by simply comparing the behavioural traits of the alleged father with that of the child.
Physical resemblance
Just because a child does not look like the alleged father does not necessarily mean that he is not the biological father of the child.
The genetics responsible for our physical characteristics are incredibly complex. For example, there are more than 100 genes involved in making skin colour alone!
Skin colour is also impacted by our environment; excessive exposure to UV rays from the sun causes damage to the skin, and the body responds by making more melanin, a natural pigment that makes our skin darker.
A new-born baby has not been exposed to the sun, meaning their skin colour may appear lighter than that of their parents.
All these factors mean that it is not possible to determine paternity by comparing the physical characteristics of the alleged father and the child.
Why should I use DNA testing to determine paternity?
DNA testing is the only 100% accurate, reliable way of establishing paternity, making it the go-to method for anyone with questions surrounding a child’s true paternity.
For a peace of mind at-home paternity test, cheek (buccal) swabs are used to collect cheek cell DNA from the alleged father(s) and the child.
These samples are then analysed and compared in the laboratory, to identify matching DNA markers (loci). Every person inherits half of their DNA from each of their biological parents, so such a comparison will help us to establish the probability of paternity.
If the tested man is the biological father, the man and the child will share DNA at every tested marker. If the tested man is not the biological father, this will not be the case.
A Blueprint DNA paternity DNA test looks at up to 25 DNA markers (loci) – over double the industry standard for DNA testing – for a 100% accurate and reliable result. We are also among the few laboratories to hold UKAS accreditation for prenatal paternity testing.
DNA testing is also the only method of determining paternity that is accepted by UK courts, provided the laboratory performing the testing is accredited.
At Blueprint DNA, we provide paternity testing to suit a variety of needs, including for peace of mind and for legal matters (e.g. child welfare/custody disputes, changing a birth certificate etc.).