As usual, the headline is at least a slight distortion of the study, not the last word.  The gist of the article is that they have proven that the bladder fills and empties during these events, but there are chemicals in the fluid that aren’t in pre-sex urine.  So I would call that a mixed verdict.  The next step, according to the article, is to find out why these things happen.

http://www.iflscience.com/health-and-medicine/women-squirting-during-sex-may-actually-be-peeing