If it's male-female breeding, then, whichever Pokémon was the female, the new baby would be that.
Pokémasters Breeding Guide
Her eyes were so dark it was hard to distinguish between her pupil and iris. The spots on her back were blacker than midnight, but all this did was to emphasise the whiteness of her coat. Lumi was the lowest female in the mob, and rightly so. No male in his right mind would mate with her, but somehow, she had managed to become pregnant. This made her even more hated. She was white as snow, weaker than a Caterpie, and to top it off, no one knew the father to her kits-to-be. Every female was suspicious of her male.
But Lumi didn’t care. She knew exactly why everyone hated her, and, had she been darker and seen another Nidorina in her position, she would have looked the other way too, insisting that she was not part of her mob, not at all. But Lumi continued on with her life, collecting grass for her nest and stocking up on leaves for the week when she knew she would give birth.
Each day, she had stared in awe at her stomach, watching it grow steadily bigger, stretching and pulling. She saw it, and felt it, when a foot went astray, kicking out at her from the inside. It was painful, but when she thought about what it meant, she smiled in happiness, and remembered back to her dark secret. The other females looked at her in disgust because of how she had managed to find a mate, the males didn’t look at her at all. She was the one making their females suspicious, why should they bother with her?
But Lumi went on happily with her life, continuing to go about her normal daily routine, until one glorious night, when she knew her life would change. During the dusk feeding time, her stomach suddenly tensed painfully, and she cringed, whining at the pain. Naturally, because of her colour, or lack there of, she had never mated before, and this sudden pain came as quite a shock to her.
The Nidoran and Nidorina around her looked up, munching on their grass, but ignored her and went back to eating.
Lumi clutched her stomach and turned, heading quickly and painfully back to her burrow. She lay down in her nest, tensing and relaxing, until suddenly, finally, a squeaking sound came from behind her. She turned to see five tiny little Nidoran, mouths wide and begging for food. Lumi guided them to her teats, then flopped down from the exhaustion of everything, listening to the racing of her heart and the tiny sucking noises from her kits. Her kits. Ordinarily her mate would be arriving with some food for her, but of course, that would never happen. Lumi just contented herself with the thought that she had finally done it, and giggled at the tickling their tiny paws made as they struggled against each other for food.
Lumi ate some of her leaves and turned to her kits, cleaning them of the blood and taking a closer look at them. As there always was in a litter of five, one was half the size of the others, the runt. However, Lumi herself was the runt of her litter, and she had survived, so there was nothing to stop this little guy from hanging on, perhaps even evolving. Lumi resisted naming her kits until they had begun to grow fur, although it was hard. She smiled down at them and fell asleep to the sounds of their sucking and intermittent squeaking when they came free of a teat.
Not surprisingly, Lumi received no visitors, but that suited her fine. The quieter things were for her, the better. She tended her kits sensitively, making sure they all got just as much milk as each other. But because her milk was not as nutritious as a darker Nidorina’s would have been, they grew slowly, not getting fur until their third day out of the womb.
The largest of them was a rich dark pink, almost purplish, like the colour of the sky as the sun disappears from it at dusk. He was the one who had been pushing at his brothers and sisters for the past few days, and who Lumi had had to pull away every now and then to let the others have some nourishment. She named him Hamara.
Hamara’s largest sister was as pale as her mother, the same icy cold blue as the sky in the middle of winter. She was the only Nidoran kit who opposed, to a certain extent, Hamara. Lumi named her Jaa.
Jaa’s sister was just a regular Nidoran, bright blue as a summer sky when the sun had risen way above the morning horizon. Her fur was fine and more delicate than that of her siblings, and she was named Aamu.
Jaa was the whitest in the litter, but her slightly smaller brother was almost as pale. Lumi was not surprised at getting two pale kits, after all, she was almost white herself. His pink was as delicate as the blossoms of the tree that hung over the warren. For this, he was to be called Kukka.
There was one missing, the runt of the litter. Lumi saw his paw sticking out from between the backs of Hamara and Kukka. She nuzzled Hamara out of the way and dropped her jaw in amazement. Now, ordinarily Lumi did not go by the fur colour rule, but now she whispered the phrases over and over, shaking her head and rubbing her eyes.
“The darker, the stronger, the lighter, the weaker. The darker, the stronger, the lighter, the weaker. The darker, the stronger”
She had always hoped, knew actually, that her tiny little runt would survive, and now there was absolutely no trace of doubt left in her mind.
The tiny kit’s fur was blacker than an Umbreon at night, blacker than the ink from a Tentacool, blacker, even, than the depths of a Cloyster. How Lumi had managed to birth a black as pitch kit was beyond her, but she now knew that her life would change, hopefully for the better. Lumi took great pride in naming him Kuu.