A number of studies have revealed evidence to suggest paternal exposure to abdominal x-ray before conception may put their children at elevated risk for acute lymphoblastic leukemia.

A case-control study published in 2010 in Cancer Epidemiology & Biomarkers & Prevention shows that if fathers received abdominal x-ray before conception, their babies were 17% more likely to develop leukemia.  If they received more than one x-ray, the risk was increased by 47%.  

If fathers received intravenous pyelogram, a special x-ray-based examination of the kidneys, bladder, and ureters, before conception, the risk for their infants to develop leukemia were increased by more than 256%.

Previous studies have already found maternal exposure to x-ray during pregnancy also associated with elevated risk of childhood leukemia.

Interestingly, the current study failed to find any association of leukemia risk with maternal exposure to abdominal x-ray before the birth or with children "having any x-rays more than six months before the censoring date". (David Liu)

Source: Helen D. Bailey, Bruce K. Armstrong, Nicholas H. de Klerk, Lin Fritschi, John Attia, Liane Lockwood and Elizabeth Milne; ; for the Aus-ALL Consortium, Exposure to Diagnostic Radiological Procedures and the Risk of Childhood Acute Lymphoblastic Leukemia, Cancer Epidemiol Biomarkers Prev November 2010 19; 2897