Serena is one of the greatest ever of all time, and if we used ability alone as the yardstick for greatness, perhaps the greatest.
But it is not her talent and ability alone that allows her to have such a schedule. It is the relative weakness of the field around her that allows her to do this. And it isn't just Serena - look at Clijsters and Henin, elite players at the time of retirement who came back after extended absences to win majors and make finals.
On the men's side, this just isn't feasible.
"I can cry like Roger, itís just a shame I canít play like him." - Andy Murray