Ever since she first became famous, Nadya Suleman has insisted that her 14 children were all fathered by the same unidentified donor. But it appears that Octomom may not be telling the truth. In an exclusive interview with In Touch, her ex-boyfriend says he believes he’s the father of Nadya’s eldest son, Elijah, 7 — and is demanding genetic testing. “I want to get a DNA test on that first kid,” says Luis Ceballos, 32, who served as Nadya’s driver during the year she spent working as a stripper at bachelor parties, private events and the San Diego club Spearmint Rhino (now called Star & Garter). Luis claims he and Nadya, 33, had unprotected “sex in the back of my limo. Right around the time she stopped stripping and disappeared, I found out she was pregnant. That is why I think the kid is mine.”

For more of Luis’ exclusive interview, check out this week’s issue of In Touch Weekly, on newsstands now!