Actress-singer Selena Gomez is "standing by her man" Justin Bieber over allegations that he fathered a child with another woman

The 19-year-old left the US Friday without Bieber, but according to the source, they are "young and in love" and she is not concerned about Mariah Yeater's claim that the 17-year-old is the father of her four-month-old son, reports contactmusic.com.