Are genital warts only transfered through sexual/ skin-to-skin contact?

My boyfriend recentley just found out that he has genital warts. He informed me that the Dr. told him that it can be caused by sexual contact, toilet seats, or wet towels. I don't have warts and have only been sexually active with him and we've been together for 4 years. Anything I've read has said that the only way to contract the infection is through direct skin to skin contact, and sex. I plan on getting tested as soon as possible, however I just want to know for sure how the disease is transmitted.

[mayflowers]

Yes, genital warts are only transmitted through sexual contact.  

I don't know what reputable Dr would tell him that he got it from a toilet seat or wet towels.  Is he really using someone's wet towels?  I wouldn't use any persons wet towels and not because of warts but because of plain old bacteria!

If people got warts from a toilet seat, then everyone would have them.  Sorry, but it's only through sexual contact.