1.   Even men who have no sperm at all or only dead sperm in their ejaculate or men whose sperm cannot swim or cannot penetrate an egg may be helped.

2.   In addition, sperm no longer penetrate eggs that have been frozen and thawed.

3.   It allowed men whose sperm do not move, men whose sperm cannot penetrate an egg and men whose sperm are not even ejaculated to become fathers.

4.   Next, one of those sperm must be able to reach and penetrate the egg as it travels from the ovary to the uterus.

5.   The extra gene was discarded with the coat as the sperm penetrated the egg.

6.   Hall is focusing on the enzymes that allow sperm to identify and penetrate eggs.

7.   Membranes covering the head of the sperm fracture on contact with the compound, leaking enzymes that are needed to successfully penetrate the egg.

8.   The sperm did not penetrate eggs, and conception failed.