PATERNAL INFLUENCE ON EMBRYOGENESIS AND PREGNANCY IN ASSISTED HUMAN-REPRODUCTION

The consequences of sperm choice for fertilization have never been mor e relevant than since the advent of intracytoplasmic sperm injection ( ICSI) in assisted human reproduction, Prior to ICSI there had always b een an element of 'natural' sperm selection in the making of an in-vit ro embryo, This de-emphasis on the need for spermatozoa of a certain q uality, at least in postnatal terms, has not led to an apparent increa se in abnormal offspring. Much precedes the delivery of a child, howev er, and to some extent long-term developmental follow-up of offspring is also necessary to confirm the present ease of acceptance of ICSI, T he possibility that a spermatozoon and its quality might have an impac t beyond that of being the simple initiator of early embryonic develop ment has intrigued some investigators, They have suggested how such ad ditional factors of sperm influence may be perceived in tel ms of conv entional fertilization in IVF with subsequent development to blastocys t, or to term pregnancy. Removal of a major hurdle, fertilization fail ure, to embryonic development and pregnancy through the use of ICSI ma y allow us to focus more specifically on the impact of the quality of a single spermatozoon on embryogenesis, and in so doing might provide more accurate analysis of the concerns that apply to the routine use o f ICSI.