Board Thread:Theories/@comment-35287381-20180521161526/@comment-24407809-20180522015302

Sure, if they have any Eldian blood in them then it's possible for them to become Titans. Reiner is proof enough of that. But that doesn't confirm whether or not they have any Eldian blood in them. Levi probably does, considering the nature of his parentage, but who knows with Mikasa.

That being said, just because it's possible doesn't mean it's going to happen, and I honestly hope this doesn't happen. Mikasa and Levi are already ridiculously over-powered by the world of Attack on Titan's standards, to the point that any battle involving one or both of them is robbed of any tension because you know they are going to win. Neither of them need Titan abilities, and giving them any would just further detract from the series' tension whenever they are involved.

Also, looking at this from an in-universe perspective, it would not make any sense to give Mikasa and Levi Titan powers. Mikasa has been referred to as being worth 100 soldiers (or something along those lines) and everyone knows Levi's title as humanity's strongest. There is no way the Survey Corps would put a 13 year cap on the lives of their 2 strongest soldiers just to power them up. From a strategic standpoint, it makes much more sense to leave Mikasa and Levi as they are, as they are doing just fine without Titan powers, and give any Titan abilities that they might get their hands on to weaker soldiers who could use the power boost. That way, their number of over-powered soldiers would increase, rather than staying confined to just Mikasa and Levi.