1967 — The couple's first son, Robert, is born.

1970 — Jane gives birth to a daughter, Lucy.

1974 — Elected as a fellow of the Royal Society at age 32, one of the youngest people to receive the honor.

1979 — Becomes Lucasian Professor of Mathematics at Cambridge, a prestigious position once held by Isaac Newton. Hawking holds the post until 2009. Jane gives birth to a third child, Timothy.

1985 — Admitted to a hospital in Geneva with pneumonia. He survives after an operation, but loses what remained of his speech. The next year he begins communicating through the electronic voice synthesizer that gave him his trademark robotic "voice."