Inquiry studies into smoking during pregnancy as a possible cause of testis cancer in sons are found misinterpreted as purely negative. Danish quinquennial incidence rates for patients aged 25-39 years are compared with rates for tobacco-induced neoplasms among the corresponding maternal generation, primarily of bladder tumours including papillomas, and of lung both for ages 50-64 years, allowing for period of latency. Corresponding to a delay of increase, earlier demonstrated for incidence rates of testis cancer among men born 1939-1945, delays of increase are found for female bladder and lung with allowance for lag-times of 30 and 20 years respectively. Comparison of data from Scandinavian nationwide cancer registries show a noteworthy parallelism of trends from first to last plotting of testis/female bladder ratios. The rise for lung is found steeper in consequence of age distribution.