April 7, 2009 10:56 am Male Biological Tick-Tock Studies show that men are about 40 percent responsible for the cases of infertility in couples in the United States. US & World Videos 1:37 Pro-Palestinian protesters gather outside White House correspondents' dinner 2:05 How ‘Love Is Blind' made Vanessa Lachey and Nick Lachey's marriage stronger 5:49 Kelly Clarkson hilariously attempts handmade pasta with chef Evan Funke 1:59 Ellen DeGeneres jokes about being ‘kicked out of show business' 2:03 Does Shakira still believe in love following Gerard Piqué split?