According to the Greek myth , Niobe boasted of her superiority to Leto because the goddess only had two children , the twins Apollo and Artemis , while Niobe had fourteen children ( the Niobids ) , seven male and seven female . According to the accounts , Niobe boasted of her superiority to Leto because the nymph only had two children , the twins Apollo and Artemis , while Niobe had fourteen children ( the Niobids ) , seven male and seven female .