People who have one of several well-documented medical conditions do not have only XX or XY chromosomes, which typically correspond with female and male sexes, respectively. Those conditions include ...

Human biological sex is determined by the sex chromosomes X and Y. In most cases, females possess two X chromosomes, while males have one X and one Y. However, there is some evidence that the Y ...

Females (XX) carry twice as many X-linked genes on their sex chromosomes as males (XY ... of tortoiseshell or calico cats (Figure 1). In cats, the fur pigmentation gene is X-linked, and depending ...

While genetics studies have identified mutations that increase the risk of developing type 1 diabetes, the gene pool alone cannot fully explain who is susceptible to the disease. Altindis and ...