Studies have shown that to become a man, you need to have at least one Y chromosome. 300 million years ago, the male specific Y chromosome contained 1438 genes at the time of its birth, but now there are only 45. At this rate, the Y chromosome will disappear in about 10 million years. 
Rhesus monkey Y chromosome gene has indeed experienced an early and rapid loss process, but no gene has been lost in the past 25 million years
 with the demise of Y chromosome, mankind will also die out.