An increased risk of congenital malformations

provides another reason for recommending that any pregnancy in subfertile couples, whether achieved naturally or through infertility treatment, is carefully monitored by a fetal medicine specialist, with detailed antenatal imaging. Given the possible link between infertility treatment and anomalies, counselling of affected couples in relation to future pregnancies may be more complex and require detailed input from clinical geneticists. Finally, what are the possible genetic causes of subfertility in a parent that are associated with congenital anomalies in a baby? Constitutional chromosomal rearrangements, including reciprocal and robertsonian translocations, and inversions are all well known causes of reduced fertility, miscarriages, and a whole spectrum of birth defects in offspring who inherit a chromosomal imbalance. In the presence of a normal karyotype, the possibility of a subtelomeric rearrangement or interstitial chromosomal deletions and duplications must also be considered. Another possibility is gonadal mosaicism in a parent for these chromosomal alterations, or other currently unknown monogenic defects. Future research should focus on establishing the mechanisms of these associations and, hence, provide improved risk assessment and counselling.