2.7 Unilateral or bilateral absence or abnormality of the vas and renal anomalies

Unilateral absence of the vas deferens is usually associated with ipsilateral absence of the kidney [53] and probably has a different genetic causation. Men with unilateral absence of the vas deferens are usually fertile, and the condition is most commonly encountered as an incidental finding in the vasectomy clinic. Nevertheless, in men with unilateral absence of the vas deferens, cystic fibrosis mutations may underlie the same genetic diseases as those with true CBAVD. In addition, it was found that men with bilateral absence of vas deferens and renal abnormalities have no CFTR abnormalities [54].

Tests for cystic fibrosis mutations should be undertaken in men who are found to have unilateral absence of the vas deference and/or seminal vesicles and normal kidneys or bilateral absence or bilateral abnormality. Ifthe results are negative and renal anatomy has not been defined, it is worthwhile obtaining an abdominal ultrasound. Findings may range from unilateral absence of the vas with ipsilateral absence of the kidney to bilateral vasal abnormalities and renal abnormalities, such as pelvic kidney.

2.8 Unknown genetic disorders

ICSI is now used to enable men with severely damaged spermatogenesis to father children in situations formerly considered hopeless and where very few spermatozoa can be obtained. This has led to worries that children may be born with foetal abnormality, because by bypassing the selective processes of female genital tract and egg coverings, defective sperm, that would not otherwise do so, might be enabled to fertilize eggs. It is therefore very reassuring that the collected foetal abnormality statistics from ICSI centres do not indicate any increase in congenital malformations compared with the general population. However, the indications for ICSI are constantly being extended to include fertilization with immature sperm forms and it will be particularly important to continue to monitor foetal abnormality rates with detailed subgroup analysis according to the clinical and molecular diagnosis of the father.

2.9 Genetic counselling and icsi

The best initial management is to give the couple full information about the risks to the child to help themdecide whether to proceed or not with ICSI.

The best initial management is to give the couple full information about the risks to the child to help themdecide whether to proceed or not with ICSI.

However, in the situation where both partners are known to carry defects (e.g. cystic fibrosis mutations), there can be up to a 50% chance of a child from the union developing clinical cystic fibrosis and dying early after a number of years of morbidity. Many clinicians and infertility clinic personnel may feel that their duty of care to the future child and the interests of society as a whole outweigh the wishes of the individual couple and that it is not ethical to proceed. When there is a conflict that cannot be resolved by agreement, the interests of a future child probably take precedence over the interests of a couple. Furthermore, the couple will need to give consideration to pre-implantation diagnosis and the replacement only of normal embryos.