Justin Bieber chatted with David Letterman about his maybe baby and the DNA test he just took -- and the kid says he\'s really not all that worried.Justin Bieber took a DNA test to prove Mariah Yeater\'s baby is not his -- and the teen pop star says he is not sweating the results.The Biebs sat down with David Letterman and said that while the situation is unfortunate, he knows it is one of the downsides of fame.\"It\'s pretty crazy. People make up false accusations. It\'s gonna happen, being in the spotlight,\" said the 17-year-old.Letterman defended the \"Mistletoe\" singer, saying he was super-ticked for the kid when he heard the news. \"I could smell a weasel,\" Letterman said.\"I can smell a weasel, too,\" replied Bieber.That intuition -- or plain downright knowledge that he never slept with accuser Mariah Yeater -- could be why Bieber was so eager to take that DNA test. If (when) it comes back proving he is not the father of the woman\'s baby, Bieber plans to sue her for defamation of character.And about that DNA test… The only body fluids involved were of the non-sexual kind.\"Is there disrobing?\" Letterman jokingly asked.\"No, no, I don\'t think so!\" Bieber responded, adding that the doctors merely took a cheek swab.Will the test be enough to satisfy Yeater\'s legal team? While they have dropped the court case, they say they still want to prove Bieber is the baby daddy. And now the mama\'s lawyer says he is not satisfied with the chain of evidence in the test because he was not present for the proceedings. Despite the fact that Yeater seemed to go MIA after Bieber gave his sample, her legal team tells TMZ she will happily give up her baby\'s DNA to prove her case.