Who is the son and mate of Gaia the father of Cronus?

The son and mate of Gaia (the Earth) who is the father of Cronus is Uranus (the Sky). In Greek mythology, Gaia and Uranus are primordial deities who represent the earth and the sky, respectively. Together, they had several offspring, including the Titans, of whom Cronus is one. Cronus eventually overthrew Uranus, becoming the ruler of the Titans.