Purpose: We provide an up-to-date summary of the genetic aspects of ma
le infertility. Materials and Methods: The literature on male infertil
ity was extensively reviewed. Results: Genetic defects are associated
with a variety of clinical presentations by the infertile man ranging
from gonadotropin-releasing hormone deficiency to spermatogenic failur
e to obstructive azoospermia. Microsurgery and micromanipulation of ga
metes make it possible for many of these men to father children. Howev
er, with each successive breakthrough in treatment of male infertility
there is an increased risk of transmitting genetic abnormalities to t
he progeny. Conclusions: Transmission of genetic defects through assis
ted reproductive techniques can have serious long-term implications. A
ssisted reproductive techniques should not be initiated in men with a
possible or known genetic cause of infertility without prior genetic c
ounseling and risk assessment. Clinicians and researchers involved in
reproductive medicine must recognize that, although these techniques h
ave revolutionalized the treatment of male infertility, they have the
risk of passing genetic abnormalities to the progeny. Therefore, resea
rchers must proceed cautiously with development and application of ass
isted reproductive technologies to avoid creating future generations o
f genetically abnormal individuals. The first step in accomplishing th
is goal is through an increased understanding of the genetic basis of
male reproductive failure.