While they (and their pr team) have denied plastic surgery rumors time and time again, it seems likely that Kim, Kourtney, and Khloe Kardashian have each gone under the knife at some point during their fame-journey. We consulted Dr. Anthony Youn, a Board-certified plastic surgeon, for his expert opinion on which procedure(s) each sister has had done. Click ahead for a guide to Kardashian Sister Surgery 101!

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According to Dr. Youn, "Kim's nose appears to have gotten a little shorter and more refined, possibly from a well-performed, conservative rhinoplasty." A conservative rhinoplasty! So there you have it; they just took a tad off the top. [Images via Kimkardashianfan.net, Getty]

Dr. Youn commented that Kim's "breasts appear overly round and full for her thin figure. This ‘roundness' is a likely sign of breast implants." And according to Tina Fey, Kim was "made by Russian scientists to sabotage our athletes." So that sounds about right. [Images via Kimkardashian.celebuzz.com, Getty]

Of Khloe Kardashian, the youngest of the three titbots, Dr. Youn observes that her "lips appear plumped, possibly from an injectable filler like Juvederm. Her lip proportions are altered. In the other photos her lower lip is larger than her upper lip…this is a possible sign of a lip enhancement." [Images via Getty, Pacific Coast News ]

As a plastic surgery expert, I was completely convinced that Khloe, too, had had some "conservative" work done to her nose, but this actually might not be the case (I am not a plastic surgery expert). According to Dr. Youn, "no obvious changes have been made to her nose." Borrrring. Your nose is a very natural and unaltered snooze fest, Khloe, and the people will not stand for it! [Images via Getty, PCN Photos ]

In 2009, Kourtney Kardashian told Life&Style that she got breast implants in college. Apparently they weren't quite what she had wanted the first time around, but after some, um, adjustments in 2009, she loves 'em. Good for you, Kourt! I am all for her finding happiness in life. So take a gander at that happily enhanced rack and enjoy. Enjoy them like she does! [Images via Getty, Bauer-Griffin ]