This must have been a fascinating series of presentations, all by deaf men. Notice the topic about deaf people marrying other deaf people. If you would like to explore this further, there has been some excellent research by Brian Greenwald on eugenics and the Deaf Community in the USA. Greenwald, B. H. (2009). The Real “Toll” of A. G. Bell: Lessons about Eugenics. Sign Language Studies, 9(3), 258–265. http://www.jstor.org/stable/26190555