He married Catherine Connelly (also a biochemist) in Holyoke, Massachusetts, On September 16, 1961. He raised a family of four children: Miguel Luis, Juan Ignacio, Jorge Eduardo and Maria Amparo and has 13 grandchildren.
With his wife, Catherine Connelly, he was on sabbatical at the University of California at San Diego, when the 1973 coup in Chile took place. He returned to Chile in May 1974 and was one of the main defenders of the University of Chile's autonomy, endangered by the military intervention in academic life. In December 1975 he co-signed, with other academics, a letter entitled "University under surveillance" opposing military intervention in the University of Chile. The letter was written by philosopher Jorge Millas and published in the newspaper "El Mercurio". The letter was the first appearance of a public statement by a group of academics who criticized the handling of the University of Chile by the military government.