It is about people with Down syndrome and the title refers to the sad reality that there are fewer people with Down Syndrome — sad because they are being exterminated in utero solely due to their genetic flaw (an extra chromosone).
…“a scene about women who choose to have abortions rather than delivering children with Down syndrome.” There’s a letter to women pregnant with children diagnosed in utero with having the condition in which the character urges them to be brave. “Thompson says she fears Down syndrome adults may be a disappearing community as fewer children are being born with Down syndrome because of genetic testing.
Dog Interacts with a Beautiful Child with Down Syndrome – Video
http://www.youtube.com/watch?v=JA8VJh0UJtg&feature=player_embedded