Worldwide, of couples trying for a child, 2-7% fail to conceive, Exten
sive screening programmes of men attending infertility clinics show th
at chromosomal and gene disorders make a significant contribution to s
permatogenic impairment, It appears that an orderly genome is essentia
l for normal germ cell development, since numerical and structural chr
omosome abnormalities are found in association with germ cell breakdow
n, The most recent research indicates that genes on the Y chromosome a
nd autosomes are involved in spermatogenic control.