that's not a sin, just a pregnant nun. It's really just a joke, no, need for getting all spiritual about it, it's actually pretty funny to alot of christians, just the irony of it. But I see nothing sinful here. I was expecting something way worse anyways.
Mary mother of Christ once looked like this and instead of sinning, it turned out that she brought one of the biggest blessings upon the earth. Re-think what you were taught. Islam is the way and the light. A continuation of the Abrahamic religions in it's purest form.