1. Your son.
2. Your father. (Henry E. Dudeney, A Puzzle-Mine, Nelson, London, c1918, #317)
3. Your wife. (Peter Storme (pseudonym for James Neuman) and Paul Stryfe (pseudonym for Philip van Doren Stern), How to Torture Your Friends, Simon and Schuster, New York, 1941, #89)
4. Sons of two men who married each other's mothers. (Henry E. Dudeney, A Puzzle-Mine, Nelson, London, c1918, #305)