Update: The bill passed 249-175 (18 Republicans for, 17 Democrats against) !!!
Many of the Republican opponents are using the argument that this bill would constitute an infringement on the freedom of speech of religious organizations. See an article from the Christian Post that makes this argument. Rep. Gohmert (R-TX) just said that the radical gay movement will use this bill to force churches to accept their lifestyle.
The National Center for Transgender Equality has a one-pager that explains why this is not true.
They will vote within the hour!