Posterior urethral valves (PUV) are a frequent cause of urinary tract obstruction in infant males and may be diagnosed by antenatal ultrasound. PUV have been observed in siblings and in identical twins. However, genetic factors in PUV are poorly understood. In this article, we report the occurrence of PUV diagnosed antenatally in a fetus whose father and paternal uncle were both treated for PUV in childhood. This is the first reported case of PUV that we are aware of occurring in successive generations.