[vog]

An even better (although quite contrived) example is given in the movie "Predestination":

http://www.imdb.com/title/tt2397535/

Alternatively, read the short story "All you Zombies" by Robert A. Heinlein, on which most of the movie is based:

http://emilkirkegaard.dk/en/wp-content/uploads/Robert-A.-Hei...