The Dink Network

I've thought A LOT about time travel (especially BACK in time) and I could rant about it for pages.. but I won't, due to the fact that I'm sleepy, but also that it can be summed up to a few lines... I think it would be impossible. Because, say someone was sick enough to want to murder his mom when she was a kid, so that he never had to see her again. Ok, so he does. Now... think about what just happened. He killed his mom before he was born. Who gave birth to him in the future so he could travel back? And since nobody gave birth to him, who did kill his mom anyway? Or another theory... say someone went back in time and murdered Hitler long before he ever did anything. How would the future look like then? If all those people were spared, if the nazis never had appeared... the world would just not be the same, and the guy who murdered Hitler may not even have been born in this "new" future, as his mom and/or dad could've found someone else to love and have kids with, cause of all the people that weren't killed... and so forth... and now I started rambling anyway.. hehe.. well... I dunno... any comments on my "theories"?