Transamerica

Bree (Felicity Huffman) is a born-again Christian and male pre-op transexual living in L.A. and trying to save up his money to become a woman. One day, he learns that he had fathered a son, Toby, who is now jailed in New York, so Bree flies across the country to get him out of jail. Toby, not realizing that Bree is his father (or a man) instead thinking she's a Christian missionary, is released to Bree's custody, and he agrees to travel with her across country back to L.A., just looking for his chance to escape from her.