As a healthy young mother a woman has a less likely chance of having a baby with birth defects such as down syndrome. As a woman gets older, near her fortys, the risk is high. When women get to this age they may not produce healthy eggs as they did when they were younger. Some women do give birth to healthy babies at this age and even older, but very few.
Men can produce healthy sperm a lot longer than women produce healthy eggs given the man is healthy. Men can produce healthy sperm well into their sixtys or even seventy, but just like women the older a man gets the higher the risk for birth defects. Unlike women, men can produce sperm all their life. If a man in his nintys is with a woman in her childbearing years (it does happen) and can no longer be sexually active he can still have his sperm removed and inserted (invitro) into her to have a child, but the chances of the child being healthy are rare.
Men can produce healthy sperm a lot longer than women produce healthy eggs given the man is healthy. Men can produce healthy sperm well into their sixtys or even seventy, but just like women the older a man gets the higher the risk for birth defects. Unlike women, men can produce sperm all their life. If a man in his nintys is with a woman in her childbearing years (it does happen) and can no longer be sexually active he can still have his sperm removed and inserted (invitro) into her to have a child, but the chances of the child being healthy are rare.