1 + 1 = 1

Mark 10:8
and the two shall become one flesh. So they are no longer two but one flesh.

This cell, formed by the union of an ovum and a sperm (Gr. zyg tos, yoked together), represents the beginning of a human being.
http://www.princeton.edu/~prolife/articles/embryoquotes2.html

Genesis 2:24
That is why a man leaves his father and mother and clings to his wife, and the two of them become one body.

The 3 exceptions: The Creation of Adam, The Creation of Eve, The Conception of Jesus.