The female chromosomes are superior health-wise and larger then males (one of them, the other is exactly the same) The male Y chromosome gives the male a disadvantage... We (males) are more prone to genetic, sex linked diseases. (including colour blindness... when was the last time you saw a female with colour blindness?.. very rare.) There are many other disadvantages to having a Y chromosome. Some people have 2 X chromosomes and 1 Y (XXY)... they are a completely other gender though. Normal people either have XX (female) or XY (male) chromosomes.