Mobs that have babies (in game):
Ziglins (Zombie Piglins) 1
Zoglins (Zombie Hoglins) 1
Mobs that do not have babies (in game):
Elder Guardians/Guardians 8b
Whatever manner reanimates different kinds of zombies seems to reanimate the young as well as adults, regardless of their species or the type of zombie (ie. husks, drowned).
Conversely, whatever reanimates skeletons does not reanimate the young, and thus they are likely reanimated in a completely different fashion to zombies. The only exception is the skeleton horse, which must in turn be reanimated in a different manner than other skeletons. Perhaps it has more in common with zombies than other types of skeletons.
2a. Whether or not wither skeletons are reanimated in the same or a similar way to other skeletons is questionable. They share the trait of lacking young with other skeletons, but are otherwise quite different.
3. The Ender Dragon does not have young, but it does produce an “egg”. Assuming it is in fact an egg, and not some strange byproduct of the beast’s biology or death, this counts - regardless of if it can be hatched by a player or not.
4. Both magma cubes and slimes are capable of asexual reproduction.
5. Salmon can be found in three different sizes. Whether these different sizes are genetic, a product of the environment, or an indicator of age is not entirely clear.
6. Allays are capable of asexual reproduction (in this case it is a magical process rather than a biological one), but they are created as fully-formed adults, and thus technically do not have any subadult phases.
7. These animals do, in fact, have young. Their young are altricial (meaning they are born unable to move or eat independently, and are dependent on the parent(s)), so it is more that they are very unlikely to be seen due to the way that they are reared.
7a. Endermen are also altricial, and hide their young in burrows to protect them from predators, competitors, and their dangerous environment.
7b. Ghasts are another altricial species. They protect their larvae within their largely hollow gas-filled bodies, in a somewhat similar manner to the mouthbrooding of certain fish and other animals.
8. These creatures are created (or suspected to be created), not born, and thus don’t have any subadult phases. These creatures are called constructs.
8a. In the case of Creakings, little is known about their nature in general. At this present time, they seem to be created by the Pale Oak, rather than having their own reproductive abilities.
8b. Guardians are constructs. but are also capable of reproducing. They typically have a eusocial colony structure similar to that of bees - the Elder Guardians being the queens, or reproductive females. Should the Elder Guardians die, however, the smaller drones can reproduce amongst themselves to produce more drones. Notably, drones cannot metamorphose into Elder Guardians like some other eusocial animals. This suggests that the different castes within their species were manufactured by their creators.
9. Similar to altricial species, these creatures do have young, they’re just unlikely to be encountered or noticed by players. In these species, it is because the young are born as very small larval stages, and are often hidden from view of potential predators - like players.
10. Creepers have consistently thwarted any attempts of study or classification. Whether they are a plant, an animal, a construct, or something else entirely, is up in the air. How, or even if, they reproduce is not fully understood.
11. The nature of phantoms is strange and little is known about them. They are undead, but do not resemble any living counterparts that could have died and been reanimated to create them. It is possible they are not animated by an external force, like how zombies and skeletons are, and instead are their own unique organism animated by other means. This makes their method of reproduction a real mystery, one yet to be studied and solved.
12. Pillagers and witches seem to be the product of environmental change in villagers. Thus, the reason their are no baby witches or pillagers is likely not because they cannot reproduce (though granted, it’s not been proven that they can reproduce), but is more likely because the young would just be villagers, and would only become pillagers or witches as they grow.
13. Wardens are bizarre and seldom studied organisms. Much of their life history is unknown, including how/if they reproduce and how/if they develop. This may be difficult to study - for a number of reasons, really, but chiefly because they are seemingly not from this realm at all, and the conditions they now live in may not allow them to reproduce or rear their young.
