1.   Another idea would be to block sperm with a contraceptive gel containing proteins that would stick to the sperm protein, keeping the sperm from from fertilizing an egg.

2.   Bleil began his search for the sperm protein about six years ago.

3.   A new generation of contraceptives could be on the way now that researchers have identified a receptor on the surface of eggs that binds to a sperm surface protein.

4.   The idea is to immunize women so that they would make antibodies against the sperm protein, preventing sperm from fertilizing their eggs.

5.   The leading stratagem for isolating the sperm protein has been to start with its counterpart, the protein it links to on the zona pellucida.

6.   The sperm protein in question is at the heart of the fertilization process.

7.   They took the mass of sperm proteins and separated them on a gel.