The micromanipulation techniques used to enhance fertilisation in both
animals and humans are reviewed, Progress in the human field is illus
trated using results of subzonal insemination and intracytoplasmic spe
rm injection from the Royal North Shore Hospital, Using knowledge deri
ved from the human work, direct sperm injection into the oocytes of do
mestic species was reinvestigated. Exogenous oocyte activation was fou
nd not to be mandatory for fertilisation, The birth of a lamb indicate
s that normal development can occur subsequent to sperm injection. The
lamb was produced from sperm that had been sorted on a flow cytometer
and was of the predicted sex. The potential uses of sperm injection f
or domestic and exotic species are discussed.