What is the “promiscuity” gene?
The “promiscuity” gene is a genetic variant of the DRD4 gene, that is associated with an increased likelihood of sexual promiscuity. This variant is also known as the 7R+ version of the dopamine receptor. It binds dopamine less efficiently, compared to the common 4R version, therefore transmitting reduced levels of the dopamine “feel good” signal in the brain. Individuals with this variant require higher levels of dopamine to achieve the same “good feeling” affects, and intriguingly sexual activity is a proven way to increase dopamine levels.

What is the function of the dopamine receptor D4?
Dopamine is a neurotransmitter or a chemical made in the brain that gives us feelings of reward and pleasure. The dopamine receptor D4 (encoded by the DRD4 gene) binds dopamine and transmits the signal into the cells.

How is the “promiscuity” gene inherited?
The DRD4 gene is located on chromosome 11. Variation in the DRD4 gene often occurs in a repeat region, where the number of repeats of a 48-bp segment ranges from 2 – 11. We inherit two copies of the DRD4 gene – one from each parent. We can inherit two identical copies (e.g. both 4R) or two different copies (e.g. 4R and 7R). Inheriting a “promiscuity” variant (7R+), is associated with increased promiscuity and an increased number of extra-pair partners.

How common are the DRD4 alleles?
The most common DRD4 variant worldwide is the 4R version and approximately 65% of the population carry this version. The 7R form is the next most common (20%), followed by the 2R allele (9%). The other alleles are less common, especially the very rare alleles that have eight or more repeats (less than 1%). The allele frequency also varies significantly between populations. For example, the “promiscuous” 7R allele is rare in East and South Asia populations (only 1.9%) but common in the Americas (48.3%).

Other conditions also associated with the DRD4 gene
Other genetic changes in DRD4 are also associated with:

• Schizophrenia
• Parkinson’s disease
• Attention deficit hyperactivity disease
• Depression
• Substance abuse
• Tourette syndrome
• Novelty seeking behaviour
• Responsiveness to anti-psychotic medication
• Eating disorders

DNA testing for the “promiscuity” gene
A simple DNA test can be completed to find out which alleles of DRD4 have been inherited. The different alleles of DRD4 are due to variation in the number of repeats of a 48-bp segment. The test determines the length of the repeat region within the DRD4 gene and specifies the number of repeats that an individual has in each of their DRD4 alleles. This test determines whether or not an individual has a “promiscuity” variant (7R+) and an increased likelihood of promiscuous behaviour.

If an individual has at least one copy of the 7R+ allele (includes 7R, 8R, 9R, 10R and 11R), they are twice as likely to be promiscuous compared to individuals with 7R- alleles (less than 7 repeats).