What? If something didn't evolve a means to reproduce, then it would die. All organisms have means of reproducing, or they wouldn't have had a way to get here.

But if you're asking about sexual reproduction, there is a clear advantage to sex: it mixes up the genes. Bacteria and other asexual organisms can only produce copies of themselves. Genetic change can only occur when the DNA is exposed to radiation or the makes a copying error. However, among sexually reproducing organisms like humans, half your DNA comes from your mother and half from your father. This makes it so that each individual has unique DNA, and the process by which better genes propagate themselves is made much quicker.