I think they're just better at detecting it these days... or at least thats part of the rise of it.
There are so many other things going on... people having kids later in life, obesity rising, people are less active (or more active in some cases than women were historically), the rise in the number of people eating fish in larger amounts that may have mercury... its hard to say what the cause is at this point, its all speculation.
Its worth hearing what the latest research show, but its by no means a proven theory yet, you know?
Funny image if you typing with it far away. The article makes it sound like the issue is more that as a child is exposed to the heavy metals through childhood, the wifi interferes with their ability to clear them out of their system.