A composition is provided, which comprises a purified cytoplasmic extract from eggs of Xenopus laevis which is capable of supporting activation of human sperm and complete replication of a human sperm genome. Methods of using the extract to achieve complete replication of the sperm genome are disclosed....http://www.google.com.au/patents/US5780230?utm_source=gb-gplus-sharePatent US5780230 - Compositions and methods for human sperm activation and quantitative assessment of human sperm genome replication 
