That's what the article linked below claims: that fathers who have produced only daughters and no sons are at a 40 % higher risk for PCa.
The presumption according to the article is that the Y-chromosome is somehow defective in these men, which, in the words of the article, "… ties Y chromosome loci to prostate cancer."
The article also claims to have found "… a strong trend for a decrease in prostate cancer risk as the number of sons increased."
The article dates from 2007, but after a quick websearch I find no updating material, so I assume the points of the article are still valid, or at least have not been challenged.
But it's also clearly just one of those statistical things. Although I myself am the father of two sons, that didn't stop the beast from paying me
a visit! www.news-medical.net/news/2007/01/03/21278.aspx
Chronic prostatitis (age 60 on)
BPH w/ urinary obstruction, 6/2011
Ongoing high PSA, 7/2011-12/2011
Biopsy, 12/2011: positive 3/12 (90%, 70%, 5%)
Gleason 6(3+3), T1c
No mets, PCa likely still organ contained
IMRT w/ HT (Lupron), 4/2012-6/2012
PSAs (since post-IMRT): <0.1