He pursed his lips, thinking his way through what she truly needed. There was something he had an idea would work, sort of a disruption of electrical output of the body causing a temporary stasis for the x-gene, but that wasn't something he was prepared to try on a mortal subject. After all, the possibility of fatality when one started playing with the body's electrical field became significantly higher.
"I assure you this is not me simply disambling, but you are presented me with quite a problem." The Doctor didn't appear to be bothered by this, but he seemed rather intrigued. "You certainly did not expect I would wave a magic wand and make it work, so I hope you're prepared to wait a while as I work on a solution for you. Also, this is perhaps the worst part, I cannot guarantee that this will not be both a painful and long process. I want to tell you this upfront because I don't want you to feel as if I've concealed anything from you when the time comes."
Full disclosure. If she was going to run for the hills, now would be exactly the time.