Can someone explain the argument that Jesus believed in Adam and Eve? It has been said that Matthew 19:4-6 indicates Jesus believed in an original Adam and Eve. I don't reach this conclusion at all. Can somebody help explain why people read it this way? 

Matthew 19:4-6


  Have you not read that from the beginning the Creator 'made them male and female' and said, 'For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh. Therefore, what God has joined together, no human being must separate."
In order to interpret what Jesus is saying in Matthew 19:4, you must first understand the reference he is making.

From Matthew 19:4:


  4 He answered, "Have you not read that he who created them from the beginning made them male and female,
  5 and said, 'Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh'?
  6 So they are no longer two but one flesh. What therefore God has joined together, let not man separate." - Matthew 19:4-6 ESV


The bolded portion above is taken from Genesis:


  20 The man gave names to all livestock and to the birds of the heavens and to every beast of the field. But for Adam there was not found a helper fit for him.
  21 So the LORD God caused a deep sleep to fall upon the man, and while he slept took one of his ribs and closed up its place with flesh.
  22 And the rib that the LORD God had taken from the man he made into a woman and brought her to the man.
  23 Then the man said, "This at last is bone of my bones and flesh of my flesh; she shall be called Woman, because she was taken out of Man." 
  24 Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh.
  25 And the man and his wife were both naked and were not ashamed. - Genesis 2:20-25 ESV


That section of Genesis is dealing specifically with Adam and Eve, and by referencing it in the way that Jesus does, he is using the correct interpretation of the law to respond to a test by the Pharisees.  As such, it is a direct reference, not a parable.   Also note that he says:


  he who created them from the beginning made them male and female


Created from the beginning as male and female, along with a direct Genesis reference to Adam and Eve is a strong indication of Jesus' acknowledgement of the veracity of the Adam and Eve account.