Three former elite U.S. gymnasts, including 2000 Olympian Jamie Dantzcher, have come forward saying they were sexually abused by a former doctor currently facing trial on a separate matter. Dantzscher, three-time U.S. rhythmic gymnastics champion Jessica Howard and former national team member Jeanette Antolin appeared on “60 Minutes” on Sunday , detailing what they have claimed is sexual abuse by Dr. Larry Nassar.