Creationists believe, naturally, that the first humans were Adam and Eve as described in the Bible. Genesis presents a historical narrative of Adam and Eve and their family. God's creation of Adam and Eve is foundational to the gospel (Genesis 3:15). There is nothing in scientific research that has been able to disprove the existence of Adam and Eve. On the other hand, Y-chromosomal Adam and Mitochondrial Eve are hypothetical humans who are the genetic ancestors of every living person. Genetic science does not prove that Y-Chromosomal Adam and Mitochondrial Eve were the first two humans to exist—it only proves that every man living today is descended from the line of Y-Chromosomal Adam, and that all people living today are descended from Mitochondrial Eve. Geneticists claim Y-Chromosomal Adam and Mitochondrial Eve lived from 100,000 to 300,000 years ago in Africa.
"Y-Chromosomal Adam" and "Mitochondrial Eve" are the names given to two hypothetical human beings who scientists have established are genetic ancestors of every living person. The Y-chromosome is one of a pair of sex chromosomes determining gender. A woman has two X-chromosomes (one from her mother and the other from her father) and a man has one Y (from his father) and one X (from his mother). Because the Y-chromosome is passed down through the male line, researchers were able to trace the ancestry of humanity backward. Likewise, mitochondrial DNA is passed from mother to both sons and daughters. This type of DNA is never passed down from the father, so a maternal line can be established using mitochondrial DNA.
By definition in this evolutionary model, it is not necessary that Y-Chromosomal Adam and Mitochondrial Eve should have lived at the same time or the same place. Genetic studies show Y-chromosomal Adam may have lived in Northwest Africa between 160,000 to 300,000 years ago. Mitochondrial Eve may have lived in East Africa between 100,000 and 300,000 years ago.
The proposed geographic origins in Africa are based on hypothetical models from paleo-anthropology, the study of the early development of modern humans. The estimated ages are based on the molecular clock mutation rate, which varies for each chromosome. Different publications apply different assumptions for the presumed clock rates. Calibrating molecular clocks backward in time for which we have no historical records involves untested assumptions. This is an area of ongoing research in evolutionary history. Creationists, on the other hand, believe that the first humans were the real Adam and Eve as described in the Bible.