When it comes to deciding the best age to have children, women aren't the only ones with biological clocks ticking.
Men who wait until their mid-30's to start a family have a greater chance of having children with genetic abnormalities, according to a National Academy of Sciences study.
Men constantly reproduce millions of sperm, but Clinical Urology professor, Harry Fisch, M.D. said that around the mid-30's, testosterone levels are on the decline and DNA mutations begin to occur.
Men in their 30's are 1.5 times more likely to have a child with autism, men in their 40's are twice as likely to have a child with schizophrenia and men in their 50's are four times more likely to have a child with down-syndrome.
Different factors, such as weight, can greatly impact the degradation of sperm quality.
Read the Men's Health full report by clicking here .
Copyright 2012 Scripps Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.