Curious---Tad left or right handed?

[kerry]

In the right thread this time:

Ida Tarbell papers have an interview with Alexander Williamson. He states that Tad was tongue-tied (too much tissue attaching his tongue to the jaw) and he urged a frenectomy, which Lincoln approved but Mary shut down for fear he would bleed to death. Probably the right decision given the state of surgery at that time. I've seen it suggested he had a cleft palate because of his speech and difficulty eating, but I've never seen a source for the latter.