Right-clicking any valid passive adult mob (animals, villagers, piglins, and zombies and their variants) with their spawn eggs does not spawn a baby version of said mob.

Steps to reproduce:

1. Spawn or find an adult chicken, pig, cow, sheep, llama, wolf, ocelot, villager, zombie, drowned, husk, zombified piglin or piglin anywhere in the world.
2. Right-click the mob with its spawn egg. No baby mob spawns.