Via: WFAA:

The age factor is pretty well known, especially among women who seem to be reminded of their “ticking clock” from relatives, friends, or strangers at some point in their lives.

However, new research shows infertility rates could be rising because sperm counts are dropping.

“All we can say is it has significantly declined with no indication that the rate is slowing down,” said Swan, a reproductive epidemiologist who spent years studying male sperm counts.

Her research found sperm counts have dropped by half in the last four decades. In 1973, the average ejaculate had 99 million sperm per milliliter. By 2011, the average ejaculate had 47 million sperm per milliliter.

“It’s not just the number of sperm. They have to be shaped well,” explained Swan, who described the upstream swim sperm have to travel for conception to occur.

In her new book, “Count Down,” Swan says based on the current curve, sperm counts could be down to zero by 2045.