Ever? Yes, as in almost always, except for pregnant women. Ronnie Coleman and Roelly (regardless of Roelly's sometimes massive gut) were born with this separation. It's more common in infants in black populations, along with umbilical hernias.
"Tissue which connect the sixpac at the middle is streched by enormous belly, and it never shrink back no matter what you do."...Not really. Pregnant women, yes.
"In men, the
most common causes for diastasis recti are obesity (causing similar pressure on the muscles), or a history of vigorous straining exercises such as sit ups or weightlifting. " -zocdoc.com
"There may be a history of
weight fluctuations, weightlifting, or full-excursion sit-up exercises, which may lead to progressive separation of the rectus muscles over time. Other etiologic factors include chronic or intermittent abdominal distension, advancing age, or familial weakness of the abdominal musculofascial tissues" -
http://www.ncbi.nlm.nih.gov/pubmed/9583506
