The male is the heterogametic sex but only has one sex chromosome. The male in XX-XO systems produce gametes with (X) or without (O) a sex chromosome.

In fact, sex determination can be very different between different organisms. For example, in the XX-XO system found in crickets, grasshoppers, and some other insects, sperm cells that lack an X ...

XO Fitness & Wellness is set to launch its first U.S. location in the Dayton area. Owner Jimmy Taylor, who started the business with two locations in Australia in 2016, said he plans to open XO ...