WASHINGTON, Aug 23 (Reuters) - Scientists have taken an important step forward in understanding the human genome - our genetic blueprint - by fully deciphering the enigmatic Y chromosome present ...

Females have a pair of X chromosomes, whereas males have a single X and a much smaller Y chromosome. The Y chromosome is male-determining because it bears a gene called SRY, which directs the ...

Most people have 23 pairs of chromosomes, including a pair of sex chromosomes that can be either an X chromosome or a Y chromosome. Having two X chromosomes usually designates a human as ...