Genetics Were Widely Misunderstood in the 19th Century.

Bell and every other scientist in the 19th Century had a poor understand of how genetics worked. Even the simplest mechanisms of genes were unknown until Mendel’s discoveries were published after 1900. Most scientists believed that traits such as deafness were hereditary and that the chances of children being born deaf were increased if their parents were both deaf.

In a 1908 article for National Geographic Magazine titled A Few Thoughts Concerning Eugenics, Bell notes that “the moment we propose to interfere with the liberty of marriage we tread upon dangerous ground. The institution of marriage not only provides for the production of offspring, but for the production of morality in the community at large. This is a powerful reason why we should not interfere with it any more than can possibly be helped.”