Male and female germ cells vary in their sensitivity to the mutagenic effec
ts of chemotherapy and radiotherapy, depending on their stage of maturation
and the agent used. Although sperm DNA damage exists following treatment,
no increase in genetic defects or congenital malformations was detected amo
ng children conceived to parents who have previously undergone chemotherapy
or radiotherapy. The use of assisted reproductive technologies and microma
nipulation techniques might increase this risk; hence caution should be exe
rcised. In female cancer patients, miscarriage and congenital malformations
are not increased following chemotherapy. However, when IVF and embryo cry
opreservation is practised between or shortly after treatment, possible gen
etic risks to the growing oocytes exist, and hence the babies should be scr
eened. During pregnancy, the potential teratogenic effects of chemotherapy
influence the choice and timing of therapy. Termination is usually recommen
ded in the first trimester, Second- and third-trimester exposure does not u
sually increase the teratogenic risk and cognitive development, but it may
increase the risk of poor obstetric outcome and fetal myelosuppression. Dur
ing the first two weeks after fertilization of the embryo, radiation is let
hal but not teratogenic. High doses of radiation during pregnancy induce an
omalies, impaired growth and mental retardation, and there may be an increa
sed risk of childhood leukaemia and other tumours in the offspring.