OK, given the ongoing discussion over Chapter 42, it seems clear I wasn't quite clear in explaining Cate's newest theory (propsals actually, since theories are more 'proofs' than concepts).
I think the biggest problem is a misunderstanding about the difference in abilities. Although the different abilities are related, they aren't the same, nor do they originate from the same things.
Both the watchers and seers are able to feel and utilize energy. This is completely separate from Alex's abilities. Their ability is genetically based, but it's governed by an odd set of rules (you can even Google XOR genetic links, though it isn't a common variation).
Alex's ability is unique to him, and until recently it appeared to have multiple levels. The main point is that he can 'activate' seers, plus he can boost watchers. However, Cate is now arguing that that ability is only a part of a larger ability. It seems his 'true' ability is being able to create these weird 'portals'. It seems his other abilities are tied to this central ability. It seems the first time Alex unconsciously used this ability, he taped into a tremendous power source. Thus it ISN'T an ability that attracts the women. Instead it's the energy 'leaking' from the portal in his head that they feel drawn to - an indirect attribute.
His ability to heal people is also an indirect attribute as it's the result of the energy he's giving off. If he tries, he can crudely direct it, but as Cate shows, it's more the result of being exposed to his 'leaking energy' that does it. the thing to remember is it's an 'accident' resulting from his primary ability to create these 'diminutional portals'. (Also note, Cate calls them 'dimentional' because she can't imagine anywhere in the known universe that Alex could be drawing this energy from, even though ALL Living things seem to require it and access it on their own.)
Now, Alex's ability to create a 'portal' allows him to 'activate' the women (he's essentially creating tiny portals inside their brains. How he can do this without crippling them is an important and unknown question, which, more than anything else, points to either Devine or Spiritual guidance, despite Alex's beliefs on the topic.
Cate's ability, on the other hand, seems to be due simply to prolonged exposure to Alex's energy. The girl's 'activation' also depends on this energy, because it seems they get their own lesser access to this energy, which is what allowed them to GROW new brain tissue to handle it's ability. It's THIS ability which seems to separate the seers from everyone else.