That sounds absurd to me!! If her other sibling animals have never had babies, it doesn't definately mean they've never mated! And if they really have never mated, she's just been lucky!!!! When I bought my hamster Patches, she was pregnant----by her brother!!!!!! She had never been mixed with any hamster besides her litter mates. (By the way, she was pregnant when I got her-I wouldn't ever keep a male and female together!!