Teen mama-to-be Jamie Lynn Spears is using the maternal example set by her bonkers big sister Brit as proof that children exposed to alcohol and tobacco in utero can turn out “fine.”

Jamie Lynn has been accused of smoking and drinking during the early stages of her pregnancy.

“Jamie Lynn knows Britney smoked and drank during her pregnancies-and because Britney’s boys turned out fine, Jamie Lynn thinks her baby will be fine too,” an insider tells The National Enquirer.