Some would have it otherwise, however.
Sex some cultures and countries, there are strong historical and contemporary preferences for males over females. Such deep-rooted preferences can produce damaging sex and even economic disparities that are difficult to remedy. Both groups' attempts have been largely thwarted by lack of an easy, affordable, and safe way to tell whether a sperm is an X or a Y carrier, or a way to increase the odds of male offspring.
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Until now, that is. According to a discovery by three researchers from Hiroshima University, there are genes unique to X sperm that can be manipulated to make them swim more slowly than Y sperm, making them quite harlem hookups to identify by fertilization clinicians, and presumably less likely in any event to win the race to fertilize an ovum.
Image source: The study, led by Masayuki Shimadafound that there are some genes active in X-bearing sperm that aren't present in the Y variant.
Of the18 encode for in receptors. Beyond the alteration in motility due to low energy production, the treated sperm were found to be otherwise unimpaired.