One click on a link generates 3 opening 2 by Mediapartners-Google ?

[Corobori]

I am having a strange issue with a website I recently created. That is a directory of website containing links to other websites. To keep track of how many times a site is opened I am tallying the number of clicks using the session id to avoid counting several times if a user opens up the same page again and again.
On my development environment everything is looking fine but I started monitoring the life website and it isn't working properly. After some research I found out that somehow the Adsense I am using is triggering extra requests to open up the page the link is triggering. I enabled the asp.net trace and here is what I could see. TopValais, le Valais sur le web is the site by the way.
Here is the trace showing the result after having clicked once on a link with the 3x reference to "OuvrirSite.aspx"





When looking at the details of the 1st request it's fine that is from my click as it appears in the IP of the remote address and the user agent.



Now looking at the details of the 2 other requests I could see that the user agent was Mediapartners-google.






In that case I tried from a Chrome browser but I have tried with IE or Firefox with the same problem

Any idea why ? I noticed the issue as my tallying was doubled or tripled when just clicking once.

[Corobori]

I removed AdSense and without it requests are just one by click !