Earth calling: A short history of radio messages to ET - space - 20 January 2010

"Joe Davis is an artist and a research affiliate at Massachusetts
Institute of Technology. In the mid-1980s, he became concerned that no
image of humans had been sent into space representing the details of
human genitals or reproduction."

http://www.newscientist.com/article/dn18417-earth-calling-a-short-history-of-radio-messages-to-et.html?full=true