To answer this question, I will split the answer into various figures, each one corresponding to a stage in the journey:
- There are approximately 200-250 million sperm in each ejaculation, but only about 2 million make it to the cervix.
- Once there, out of the 2 million sperm entering the cervix, only about 1 million are able to make it to the uterus.
- Out of the 1 million that enter the uterus, only 10,000 are able to travel to the top of this organ.
- Out of the 10,000 that survive at this point, only half of them travel in the right direction, that is, toward the egg cell.
- Out of the approximately 5,000 sperm that enter the utero-tubal junction, about 1,000 get inside the Fallopian tube.
- Finally, out of the 1,000 that enter the tube, it is estimated that only 200 make it to the egg.
However, in the end, only 1 sperm out of the 200 that reach the egg is able to penetrate and fertilize it.
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics.