Males who are in their fifties are still capable of making offspring whereas females may not. How is this...?

This is because females undergo menopause - an event in every woman's life in which their menstrual cycle ceases and they are thus unable to produce eggs or biologically support the development of a fetus. Men do not undergo this process, and (assuming good health) are usually able to produce viable sperm for their entire life.

Meiosis is the reduction division of cells which, in humans, produces haploid gametes (i.e. sperm and eggs). Eggs are no longer produced in menopausal women, so meiosis ceases to produce viable eggs in these women.

It's because men are better than women.