Impact of age on male fertility
The Male Biological Clock is a Reality not known by most doctors and layman. NW Cryobank accepts sperm for donation to 35th birthday to prevent genetic disorders. Geneticist James F. Crow, PhD said that fertile old males (34+) (my research) are the greatest mutational hazard on earth. Family history is also crucial. Don't delay starting and completing your family because age does matter.
Rate of de novo mutations and the importance of father's age to disease risk. Kong A, Frigge ML, Masson G, Besenbacher S, Sulem P, Magnusson G, Gudjonsson SA, Sigurdsson A, Jonasdottir A, Jonasdottir A, Wong WS, Sigurdsson G, Walters GB, Steinberg S, Helgason H, Thorleifsson G, Gudbjartsson DF, Helgason A, Magnusson OT, Thorsteinsdottir U, Stefansson K. Nature. 2012 Aug 22;488(7412):471-5. doi: 10.1038/nature11396. PMID: 22914163 [PubMed - in process]
http://www.ncbi.nlm.nih.gov/pubmed/22733127