Wow, this episode is just bad. I mean, it is one thing to touch the inevitable topic of procreation of crew members on a space ship that won't be home for a long time. But in this episode, the sex topic is constantly rubbed in the viewers face - and not in a subtle way.
First, Chakotay surprises a kissing couple in the turbolift and is concerned. He talks to Janeway and they philosophize what will happen if crew members get pregnant. If the ship would be able to care for the children and give them proper education. Relationships between crew members have always been in thing in Star Trek. See TNG. I do not know why Chakotay suddenly thinks, that this won't or should not happen on the Voyager. If males and females are locked in confined spaces for an extended period of time, nature takes its toll on the crew.
Then they encounter a swarm of space sperm that is attracted to their ship and pulls them closer. There is even a bigger life form in that swam that sees the space ship as a competitor in this mating ritual and attacks it. It only loses interest, after the Voyager rolls over and presents a submissive posture.
And last but not least we have Kes, that is somehow affected by the radiation of the space sperm and her puberty phase starts so rapidly, that she either has to procreate in the coming days or will never be able to have a baby. We see and hear some disgusting changes to her body and have to witness discussions between Kes and Neelix if they want to have a baby or not. The relationship between the two is a strange one anyhow and not interesting to follow. I had no pitty with both of them. They have zero romantic chemistry - in the contrary: Neelix is a jelous dick that acts very possessive, too. I think most viewers were relieved that Kes ultimately decides against having a baby. Those two just have nothing in common and Neelix would be a terrible dad. He already is a terrible, annoying person and should have been jettisoned out of an airlock numerous times.
And how comes, that every species in the Star Trek universe is able to have offspring with other species? It is like a cow and a horse would try to mate. Both look similar, they have four legs, hooves, tails, eat grass, are herd animals... in Star Trek logic this should be possible without any problems. And those two species even come from the same planet and have a common evolutionary ancestor - they did not evolve thousands of light years apart on different planets from different genoms in different environmental habitats.