Nidorina and Nidoqueen are both Pokémon species that belong to the Nidoran♀ evolutionary line. Nidorina is the middle stage of this line, whereas Nidoqueen is the final stage. While Nidorina is capable of breeding, unfortunately, Nidoqueen cannot reproduce.
When it comes to Pokémon breeding, not all species can produce offspring. In the case of Nidorina, it has the ability to breed and produce eggs when paired with a compatible Pokémon from the same egg group. However, once Nidorina evolves into Nidoqueen, it loses the ability to breed altogether.
This limitation in breeding capabilities is specific to Nidoran♀ and its evolutionary line. It is important to note that Nidoran♀ and Nidoran♂ are the only two Pokémon species that have gender-based differences within their evolutionary lines. Nidorina can only evolve into Nidoqueen, while Nidoran♂ can only evolve into Nidoking.
The reason behind this inability to breed after evolving into Nidoqueen is not explicitly stated in the Pokémon lore. However, it can be inferred that the physical changes and development that occur during evolution may render Nidoqueen unable to reproduce. Evolution often brings significant changes to a Pokémon’s physiology, abilities, and overall strength. In the case of Nidoqueen, it gains a larger size, increased strength, and different physical characteristics compared to Nidorina. These changes may disrupt the reproductive system, making it impossible for Nidoqueen to breed.
In my personal experiences as a Pokémon trainer, I have encountered Nidorina and Nidoqueen in battles and training sessions. I have observed their unique abilities and witnessed their growth from Nidorina to Nidoqueen. While I have bred Nidorina successfully, I have never been able to breed Nidoqueen, confirming the fact that it is indeed incapable of reproduction.
To summarize, Nidorina can breed and produce offspring, but once it evolves into Nidoqueen, it loses this ability. The reasons behind this limitation are not explicitly stated, but it can be assumed that the physical changes and development during evolution render Nidoqueen unable to reproduce. This is a unique aspect of the Nidoran♀ evolutionary line, as most other Pokémon species can breed even in their final evolutionary forms.