Son of a Preacher Man was never recorded by Janis Joplin. Not in the studio, not live, now anywhere. I doubt she would even have hummed along to it. [ Lyrics from: http://www.lyricsmode.com/lyrics/j/janis_joplin/son_of_a_preacher_man.html ]
Why don't you remove this error from your site. It perpetuates an Internet and urban legend that is simply not true.
Janis joplin did sing son of a preacher man but it was never copyrighted and was never released by any record label. The song was rarely performed and never at a live concert event and any video of her singing son of a preacher man is rare and worth a lot money so in a sense she is correct when she said that it was never recorded and she is correct when she said it was never sang live that song was only sang in front of private family functions. Which means she is over all correct in legal means basically its a hard song to obtain and the actual lyrics were never found. It's a lost classic. Now how do i know this be cause she is family. So lets leave it at that.