Either Schiano is lying, or another PSU coach, Mike McQueary, is lying.
Let's break it down, what motivation does MM, have for lying? What does he stand to gain? Can anybody think of a reason.
So what does MM stand to lose by lying? Well, a lot, because his statement is under oath.
Schiano, by admitting it, would probably lose his job, and definitely his reputation. By lying, he keeps his job, his reputation, and since it's his word against MM, and he's not under oath, he has literally nothing to lose by lying and claiming MM is the liar.
So, Schiano has everything to gain and nothing to lose by lying, McQueary has nothing to gain and plenty to lose by lying.
You make the call.