While on a delivery mission Amy stowaways onboard the ship so that she can meet up with her boyfriend Kif. Amy is suprised to discover that Kif is pregnant and that she is about to become a mother.
Although Amy is the 'smizmar' the person who induced the state required to conceive she may not actually be the person who contributed the DNA. Anybody who has touched kif may be the actual parent.
There is a really cool scene of the characters spinning around inside the professors machine and being spat out one after the other when it determines they are not the parent.
Kif's relieved look when Zapp is spat out is only offset when Amy is also spat out leaving only Leela the parent inside.