[The joys and burdens within clinical genetics--paternal discrepancy causes dilemmas].

We present three cases, a 25-year-old woman, a 52-year-old man and a 45-year-old woman, in whom paternal discrepancy (PD) adversely influenced genetic counselling. PD, with an estimated prevalence between 2% and 3%, occurs when a child is identified as being biologically fathered by someone other than the man who believes he is the father. The discovery of PD during genetic testing can cause health problems and psychosocial damage, and can increase costs, as illustrated by our three cases. Opinions vary about whether or not to disclose this sensitive information, and we recommend being as straightforward as possible, while trying to minimize any harm caused. Since genetic techniques that identify PD are improving and increasingly applied, health care providers must be prepared to deal with issues of this nature.