Would their child be a regular reindeer; A Half Reindeer-mink. . .
Clearly Chopper had a crush on Milky; and Milky did nuzzle chopper's face with her own facial cheeks. . .
So What would happen if these two Reindeer humanoids that love each other very much were to try and Score. . .
I've thought about this a lot: do Zoan Fruits alter the Lineage Factor in your sperm? We know that Lineage Factor determines the characteristics of beings in the One Piece world, so, it must be found in Ovum and Sperm.
However, we've never seen an instance of Devil Fruit Powers being passed on via reproduction. Kaido ate his Fruit most likely before Yamato was conceived, as he received his Fruit from God Valley, and Yamato was born a decade later.
Since Yamato has no Fish/Dragon elements, it's safe to say the Lineage Factor from Zoan Devil Fruits does not affect the Sperm/Ovum of Fruit users... OR, it's a trait that needs to be matched.
If the genes for Zoan Devil Fruits found in the Lineage Factor are recessive, not dominant, it's possible that two people with the same Fruit mating could cause a baby to be born with Devil Fruit Powers.
IE: Kaido and Momo have, more or less, the same Fruit. If Kaido and Momo mated, it's possible their child would have the Lineage Factor of a Dragon, and the ability to transform into a Dragon.
Since Milky IS a human-reindeer Hybrid, as Minks are Humanoids with animal features, and Chopper IS a human-reindeer Hybrid, it is possible that their Lineage Factors could prove a human-reindeer child with transformative powers like Chopper.
We won't fully know until Chopper impregnates Milky.
We'd get a Reindeer Mink, that could possibly transform into different forms. If the Lineage Factor from Chopper's Fruit doesn't go through, we'd get more Reindeer than Human.
Finally, if Chopper's Lineage Factor from his Human Fruit ISN'T present in his sperm, there's a chance Chopper can straight up not reproduce with Milky.
Since Minks are humanoids with full coats of hair/fur (we still don't know if the Minks shed or not) and animal characteristics, we're not sure if they can mate with humans/other animals. So far, we have no character produced by a Human mating with a Mink (as far as I know), and we likewise have no proof that Minks can reproduce with normal wild animals.
If the Human Fruit isn't present in the Lineage Factor in Chopper's Sperm, Milky would have to be able to reproduce with... uh... actual Reindeer in order to be able to make a child with Chopper.
So, if Milky banged Chopper's Dad, who is just... a normal Reindeer, could she produce a child?
So, long story short, we need to figure out if the Human Fruit's Lineage Factor is present in Chopper's Rumble Balls.
Time to send Oda a question asking if Chopper's Dad could knock up Milky. Hehhhhhhhhhhhhhhhhhhhhhhh.
Furthermore, this opens up a lot of questions on how Minks, Fish-Men, and Merfolk came to exist in the first place.
Is this like the Pokemon leaks, with the Fisherman that just banged an Octillery?
We may never know.