J. B. S. Haldane
On 12 December 1891 he married Louisa Kathleen Coutts Trotter (1863–1961), daughter of Coutts Trotter FRGS and Harriet Augusta Keatinge. They had two children: the scientist J. B. S. Haldane and the author Naomi Mitchison. His nephew was the New Zealand doctor and public health administrator Robert Haldane Makgill.