ON THE ORIGIN AND FREQUENCY OF Y-CHROMOSOME DELETIONS RESPONSIBLE FORSEVERE MALE-INFERTILITY

The origin of deletions associated with non-obstructive severe oligozo ospermia in men are discussed. Deletions could arise during various st ages of meiosis, at later stages in spermatids, or post-fertilization. Certain embryonic stages may be highly sensitive. The possibilities o f an inherited propensity to these and other deletions, and of mosaici sm in embryos are assessed.