Junior boots are (always? mostly?) softer than an adult model, sometimes is the plastic different.
Lange World Cup (adult) has Lange index 130, made of polyether.
Lange World Cup (junior) has 100,
the adult Comps are 120 and 100, the juniors only 80, 70 and 60.
The women´s boots are usually lower and there is more space at the cuff to accomodate the w. calf.
The women´s liners are often softer, with more padding, using materials known as especially warm (at least that´s the description they mostly bear).
There are some more minor differences.