Sperm Gender Check

The development of the SpermGenderCheck.

Sub Link: Why SpermGenderCheck is necessary

We know it has been reported that men with more brothers had a higher probability of having sons and those with more sisters had a higher probability of having daughters. Similarly, an increase of Y sperm in men with only sons (>3) or the X sperm in men with only daughters (>3) has been reported. 

Yet these claims were based on unsubstantiated theory, using relatively nonspecific methods to differentiate between the X and Y sperm. 

To provide parents with a better assessment of the likelihood that they will produce a male or female child, we have developed a very specific, real-time polymerase chain reaction (qPCR) test with unique primers to determine the real differences between the two sperm types. We tested the technology with sperm samples from 50 randomly selected men, and documented the results. We published our findings (Jeyendran et al., 2021), which confirmed that there is truly a difference in prevalence among the two types of sperm between individuals. We found that the percentage of Y sperm ranged from a low of 23% to a high of 63% – a dramatic range.

Why SpermGenderCheck is necessary

These findings have implications for parents trying to conceive a child of a particular sex through gender-based sperm enrichment procedures, whether they are trying to minimize the chances of a sex-linked genetic disease, or are undertaking the procedures in the interest of family balancing.

As noted earlier, there are many theories about the reason(s) for the variation in the ratio of X sperm and Y sperm in an ejaculate, but the observation itself appears to be consistent. A man will produce the same ratio of X sperm to Y sperm in every ejaculate he produces. Therefore, if a man who has a greater preponderance of X- sperm in his ejaculate were to be subjected to a Y-enrichment procedure, the chances of conceiving a son are still unlikely to rise above the average 50%. This is a consideration that the prospective parents will want to take into account before embarking on costly treatments.

For these reasons alone, it will be prudent for couples to check their semen sample for gender-specific sperm numbers as part of their decision-making process. 


  • Jeyendran RS, Graham J, Tharma S, Ivanovic M, Levrant S, Ozornek HM, and Fiddler MB. (2021) Individual variation of the percentage of Y-chromosome bearing sperm content in human ejaculates, Systems Biology in Reproductive Medicine, 67:5, 395-398, DOI:10.1080/19396368.2021.1942589