Yes, some men may produce more X sperm, which leads to a higher chance of having daughters. This is influenced by a gene that determines the percentage of X and Y chromosomes in sperm.
- Men with the "mm" gene combination produce more Y sperm and have more sons.
- Men with the "mf" combination produce roughly equal numbers of X and Y sperm, resulting in an even split of sons and daughters.
- Men with the "ff" combination produce more X sperm and have more daughters.
This genetic influence on sperm production is still being studied, but it offers an explanation for why some families have a higher percentage of male or female offspring.
