3 DNA Tests for Infidelity

A DNA infidelity test can be a useful tool if you suspect that your spouse or partner has been unfaithful. In this article, we look at the three most common infidelity-related tests and explain how they work. We also examine why it is important to understand the accuracy of these analyses, as well as the limits of each method.

A DNA infidelity test is a genetic analysis used to detect another person’s DNA on an object or surface. This type of testing is also related to methods used in forensic investigations involving bodily fluids and biological traces.

The Semen Detection Test

The semen detection test is a simple way to determine whether a stain you have recently found may contain traces of semen. In practice, this is a semen screening analysis that can be carried out on many different types of surfaces.

Samples are then analysed by laboratory technicians, who report a result as either positive or negative.

You will not have access to the person’s genetic profile.

This type of test can still be carried out even when the sample is old. Because the aim is not to establish a full genetic profile, precision at that stage is not the main issue. As a result, laboratories may sometimes perform semen detection on samples that are several years old.

If you want to understand this first step in more detail, you can read the article on the sperm detection test.

The Genetic Profiling Test

The genetic profiling test is a highly precise way to determine whether DNA is present on a surface or object. This analysis can provide several types of information:

• It can determine how many DNA profiles are present. In some cases, a sample may contain DNA from more than one person.

• It can determine the sex of one or more individuals. In addition to identifying how many DNA profiles are present, the laboratory may indicate whether the detected DNA is male or female.

• It can establish a genetic profile, depending on the quality of the sample.

If your sample is very old, the DNA on it may have degraded over time. In that situation, the laboratory may be unable to establish a usable genetic profile.

To learn more about how this analysis works, see the page on the DNA genetic profile.

The Saliva Comparison Test

The saliva comparison test is actually an optional step that may be offered after a genetic profiling test.

This test works by comparing your saliva DNA with the genetic profile obtained during the profiling analysis. Naturally, this option is only possible if the original sample has provided enough usable genetic information during extraction.

The results indicate whether your DNA and the detected profile share identical genetic markers on your chromosomes. However, if the result is different, you will not be given access to the other person’s genetic profile.

Everything comes down to consent. If the laboratory identifies a genetic profile for which no consent has been given, the genetic information cannot be shared with the person who ordered the test. You may still be told that the analysis is inconclusive and that the DNA found on the object is not yours.

If you are unsure how such reports are presented, the guide to DNA test results can help you understand how laboratories report genetic findings.

How Accurate Is a DNA Infidelity Test?

The accuracy of a DNA infidelity test can vary depending on both the type of test performed and the quality of the sample.

Reliability also varies from one method to another. A step-by-step approach is generally recommended, starting with semen detection, which is often enough in many situations.

For the best chance of obtaining interpretable results:

• use a recent sample whenever possible;

• remember that the older the sample is, the greater the risk that the DNA can no longer be detected;

• only use samples that belong to you or samples for which valid consent has been given.

In the United Kingdom, accreditation and validated laboratory procedures are important quality markers for forensic DNA work, especially where biological traces and body fluid recovery are concerned. You can read more about this through UKAS forensic laboratory accreditation.

Consent for an Infidelity DNA Test

When carrying out an infidelity test, the laboratory must take particular care to analyse a surface or object that belongs to the person making the request or for which testing is lawfully authorised.

Here, consent can be a double issue, and the owner of the object may refuse to allow the test to be performed. Since there is a strong chance that the owner’s own DNA is present on that object, they may exclude their consent from the genetic analysis, especially if they are not the person ordering the test.

The second consent issue concerns any DNA found on the object. If you want access to the other person’s genetic profile, you would need the saliva comparison option with your own sample. But if the result does not match, the laboratory will refuse to disclose the other person’s genetic information.

In England, DNA sampling generally requires the consent of the person tested, or of someone with parental responsibility where relevant. The GOV.UK guidance on DNA test consent and refusal gives a useful overview of this principle.

Please note that an infidelity DNA test cannot be used as legal or administrative proof.

Is a DNA Test the Only Way to Confirm Infidelity?

A DNA test for infidelity is only one possible way of finding out whether your spouse has been unfaithful. If you suspect your partner is cheating, a DNA test may help clarify the situation, but it is not the only possible route.

Many people in this situation do not choose a DNA test because they want definitive proof and consider the process costly or time-consuming. Some instead think about hiring a private investigation company to monitor the suspected partner’s movements without their knowledge, in the hope of obtaining photographs or videos. That said, the legal and ethical implications of such steps should always be considered carefully.

Infidelity is a serious issue in any relationship. Some couples manage to preserve their marriage after infidelity has been discovered and addressed, while for others the consequences are much harder to overcome. If you want to know whether your spouse or partner is cheating, a DNA test may be one possible solution depending on your situation. It is therefore a highly specific personal-use analysis and should not be confused with a legal paternity test.