Works from english to portuguese in google, maybe because they have more data? Considering this example alone, the logical difference between english/spanish and english/portuguese are pretty much the same: gender is made explicit in the pronoun in spanish/portuguese(primo/prima) in contrast with english that relies on an adjective(her). About ambiguity, biases, well, what the "machine" learns are pretty much biases, meaning it's biased by the data it was trained on.