Title (of the article) likely to be misleading:<p>The allergic reaction is not itself sexually transmitted.
The brazil nut allergen is sexually transmitted (via semen) causing an allergic reaction in someone known to be allergic
This was covered on qi:
<a href="http://www.youtube.com/watch?v=f4Ktn7YXoJQ" rel="nofollow">http://www.youtube.com/watch?v=f4Ktn7YXoJQ</a>