NEW YORK (Wireless Flash) -- Birth control pills and condoms may rub you the wrong way but they're a definite improvement over what the ancients used.

That's according to sex experts Erica Orloff and JoAnn Baker, who say the idea for the I.U.D. was originated by Arabian camel herders who discovered sticking a stone in a female camel's genitalia would keep them from getting pregnant.

Other cultures with bizarre birth control methods include ancient China, where the women terminated pregnancy by drinking hot mercury the day after sex and ancient Persia, where the ladies used sea sponges soaked in alcohol as primitive contraceptive sponges.

Orloff and Baker discuss other bizarre sex stats in a new book, "Dirty Little Secrets" (St. Martin's Griffin).