amount of sperm per ejaculation
The average sperm count fell from 113 million sperm/ml of semen in 1940 to 66 million/ml in 1990. The volume of a single ejaculate has declined from 3.40 ml to 2.75 ml. This means that men on average are now ejaculating less than half the number of sperm as men did 50 yrs ago. A drop from more than 380 million sperm to about 180 million sperm per ejaculate. Furthermore, the number of motile sperm has also dipped.