Chemicals found to separate X-sperm from Y-sperm could allow for sex selection

Chemicals found to separate X-sperm from Y-sperm could allow for sex selection. Experts at Hiroshima University have identified chemicals that suppress the survivability and motility of sperm that carry the X chromosome. According to a report in New Scientist, scientists are warning that this discovery could lead to the development of products for home use that would make couples much less likely to conceive a girl.

A team led by Masayuki Shimada identified 492 genes that are active in sperm that carry the female X chromosome, yet are not active in sperm that carry the male Y chromosome. Chemicals found to separate X-sperm from Y-sperm could allow for sex selection

“Among these genes are members of different classes of receptors that have the potential to mediate sperm responses to factors in their external environment, such as chemokines, creatine, progesterone, and pathogens. Thus, functional differences of X-sperm and Y-sperm can be identified and provide a novel approach for specifically selecting X-sperm or Y-sperm,” wrote the study authors. 

Many of the genes unique to the X-sperm were found to code for proteins that protrude from the surface of the sperm. The experts demonstrated that certain chemicals can bind to two of these proteins and slow down the movement of X-sperm without affecting Y-sperm. 

Using a mouse model, the team showed that the selection of the slower sperm resulted in offspring that were 81 percent female, while the faster sperm produced 90 percent males.

Alireza Fazeli of Tartu University told New Scientist that these chemicals could be potentially added to gel or foam products that would be applied inside the vagina before sexual intercourse to greatly increase the chances of conceiving a boy.

“I am concerned about the social impact of this,” said Fazeli. “It’s so simple. You could start to do it in your bedroom. Nobody would be able to stop you from doing it.”

Such products would likely be in high demand in countries that already favor one gender over the other. Bioethicist Wybo Dondorp told New Scientist that, in these types of countries, “it is clear that if there are more easy, cheap, accessible technologies they will be used.”

In 2016, there were 33.59 million more men than women in China, according to the country’s National Bureau of Statistics.

The study is published in the journal PLOS Biology.

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By Chrissy Sexton, Earth.com Staff Writer

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