Pregnancy won’t happen unless a sperm makes it to the egg. After ejaculation, up to 150 million sperm is released, but only roughly 15% of those will be perfectly normal sperm that can penetrate an egg. Most persons fail to understand that fertilization is a process. One of the things fertilization requires is a healthy sperm. After ejaculation, the sperm have to swim through the cervical mucus and cervix, and up the fallopian tubes. The fastest of the sperm can take about 30-45 minutes, the slowest, up to 12 hours while the others can take days. Most sperm never make it. They either run out of energy and give up, go in the wrong direction or get trapped. Some sperm have been killed off by natural antibodies or hostile cervical fluids. In the end, it’s just a few sperm that finds their way to the egg.