Study: Men of All Ages Want Women in Their Mid-20s

[Xithras]

366. Sperm degradation typically results in decreased motility.

There is absolutely a way of knowing that, and it's basic male biology. Severe degradation of male sperm usually results in decreased motility. The less healthy a sperm is, the slower it tends to move. Since a normal male ejaculation results in the implantation of millions of sperm cells, higher motility rates cause the healthiest sperm to reach the ovum first. While there are certainly a large number of birth defects that can be transmitted while motility is maintained, the most degraded are weeded out by the nature of the fertilization process.

Yes, the odds of birth defects resulting from older fathers DO increase, but it's at a rate substantially lower than what is experienced by women. At age 50, the odds of a womans pregnancy resulting in a child with birth defects is about 1 in 40. For 50 year old males with younger females (25), the rate is closer to 1 in 1000. While that number is substantially higher than what a 25 year old woman would experience with a 25 year old man (roughly 1 in 1400), it's still a far lower defect rate than that experienced by women as they age.