Interpretation Born of Theological Necessity
One explanation that has become popular among many Evangelicals is that Jesus was really talking about the first, physical birth when he referred to water. Evangelicals attempt to make verse 5 parallel to verse 6. They argue that in verse 5, only the words, "the spirit," have reference to the new birth. They take "born of the water" in verse 5 to be equivalent to "born of the flesh" in verse 6. In order to sustain this awkward connection, they refer to the water that breaks prior to the birth of a baby.
It seems so far-fetched as to be hardly worthy of notice. But even things that are ridiculous can begin to sound reasonable if they are repeated often enough. Therefore, we will address this Evangelical explanation.
First, if the words of Jesus recorded in verse 5 were intended to mean "One must be born not only physically, but also spiritually," why didn't Jesus say that? He could have said, "One must be born of his physical mother and also of the Spirit," or "One must not only be physically born, but also spiritually." Why would he have said "born of water"?
Here the Evangelical (feeling a bit embarrassed as he realizes how unlikely his claim really is) reminds us that water breaks before a baby is born. But does anyone really speak of physical birth in terms of that water? For that matter, I doubt most men in most societies even associate water with birth. Most of us weren't very familiar with this particular aspect of childbirth until we became fathers ourselves. That is, unless we are Evangelicals and were taught this fact of physiology by a pastor trying to explain away John 3:5. I suppose here we might allow that Evangelicals have demonstrated great leadership in the field of sex education, making so many aware of this aspect of childbirth.
Satire aside, my point is that "born of water" is simply not a natural way of referring to physical child birth. For that matter, the baby doesn't even go through the water!
Evangelicals strive to make this explanation work because the obvious meaning of the passage doesn't fit their theology. They ignore the context of John's baptism. They ignore what Jesus' explanation would have meant to Nicodemus. (He certainly would not have thought "born of water" was a reference to the mother's water breaking.) The problem isn't with the passage. It is with Evangelical theology.