Well, perhaps defining strength would be needed. As I understand it for muscles there is basically going to be no difference between a long time FTM on T and a cismale. I do know however, that cismen have larger hearts, lung capacity, etc on average, but I am uncertain if being a long time on T increases those things closer to the cis average or not. Even if it didn't that seems like it would be an endurance thing, not a strength thing, though I would imagine that at the highest levels of strength training it could have an impact. So far as I know there isn't really studies out there about this.
The IOC seems to beleve that someone who has had reassignment surgery, two years on HRT, and has the legal paperwork for their new gender has no advantage over their cisgender peers and seeing as trans athletes are not dominating the Olympics I would imagine they are vindicated in that position; still WADA requires an Therapeutic Use Exemption for T. This lets WADA impose conditions (such as how much T) if they so desire, which seems to be a bit over involved to me, but luckily since I am going the other direction (and am not even an athlete) it doesn't really apply to me.