There is ample evidence for Adam & Eve's existence approximately 6000-7000 years ago. That said, I'm not a young earth creationist, I believe in two creation events. Genesis chapter 1 is who we term Neanderthals, and Genesis chapter 2 is Adam & Eve. The Gen 1 event was probably many millions of years ago, and Gen 2 was approximately 6000 years ago. But God destroyed the seed of Gen 1, it no longer exists today. I believe the Gen 1 seed was too corrupt to bring forth the messiah, so God started a "new line"
Science proves everyone alive today is related to the exact same "set" of people that existed 6-7000 years ago. And if there was anyone else alive 6000 years ago not related to any of us, they (their DNA) no longer exist on earth today. This is exactly what creationism predicts
"Modelling the recent common ancestry of all living humans" Douglas L. T. Rohde
"If a common ancestor of all living humans is defined as an individual who is a genealogical ancestor of all present-day people, the most recent common ancestor (MRCA) for a randomly mating population would have lived in the very recent past...Here we show that recent common ancestors also emerge from two models...These analyses suggest that the genealogies of all living humans overlap in remarkable ways in the recent past. In particular, the MRCA of all present-day humans lived just A FEW  THOUSAND YEARS AGO in these models. Moreover, among all individuals living more than just a few thousand years earlier than the MRCA, EACH PRESENT DAY HUMAN HAS EXACTLY THE SAME SET OF GENEALOGICAL ANCESTORS"
"Family tree shows our common ancestor lived just 3,500 years ago" Michael Hopkin
"The most recent common ancestor of all humanity lived just a few thousand years ago, according to a computer model of our family tree. Researchers have calculated that the mystery person, from whom everyone alive today is directly descended, probably lived around 1,500 BC in eastern Asia"
"Besides dating our most recent common ancestor, Rohde's team also calculates that in 5,400 BC everyone alive was either an ancestor of all of humanity, or of nobody alive today. The researchers call this the 'identical ancestors' point: the time before which all the family trees of people today are composed of exactly the same individuals"