New research seeks to prove that the idea that sperm win or lose the race to fertilize the egg is false.
According to Dr. Joseph H. Nadeau, the egg is in charge of selecting the ‘winning’ sperm, under the term of genetically biased fertilization.
Nadeau propped up his theory from experiments in mice, in which he added a normal gene and a mutant gene (cancer) in females, while male mice had all of their normal genes. As a result, what was already known was obtained: each parent carries two copies of each gene and fertilization is done randomly.
He then performed the experiment in reverse, adding a mutant and a normal gene to the male mice. Contrary to what would have been expected, only 27% of the mice had the gene with cancer.
This proved that fertilization is not random. That it is not a sperm race, but rather an egg selection process.