Jack O- actually, two men can have a product of their own DNA now days. all that is needed is the protein in an egg- which can be created by science. it's egg nucleus transfer- you remove all female DNA from the egg (or no female DNA if you create the egg), then inject both males dna in the egg... the offspring? of course, will be male 100% of the time. Anand99- it's simple- it's a very famous jewish cook. the answer is no other than hitler. he had the biggest impact that anyone might have had in all of history- though partially due to the fact we were already recording history. whereas other great or aweful leaders in the past thousands of years had marginal to little (or limited) written history to glorify their accomplishments. i can safely presume that the reason hitler was not voted the most influential person of the century 8 years ago (for the 20th century) is due to the fact people would deem it as a gross injustice to glorify such an evil man. seriously, the questions was not who had the most positive impact, it was who was the most influential. you just simply cannot find someone who influenced the course of history more than him. to answer your question, we learned a lot from him and we are bound to never repeast his actions. greatest contribution- perfect example of humans lowest, most dipicable, most ugly and saddest depths, to never be repeated. and if you attempt to find someone else, there are well over 50 million people who can prove my point- all are dead but you get my point.