To indicate two different genders, you could say "Mwanaume asingalikuja, mwanamke asingalipika," but I think if you just want to indicate that it's two different people, I think you might use a demonstrative such as huyu for one or the other, but I'm not exactly sure. I think the reasonably interpretation of the Swahili sentence given here is that it's only one person though, so I'm sure the English sentence given is just a bit off and maybe an oversight.