The real Mowgli is nude of course. How would a child living in the wild get clothes (it has never even heard about something like it). Mowgli in The Jungle Books is always nude, except for the period when he went back to the village.
Part from Tiger! Tiger!
For three months after that night Mowgli hardly ever left the village gate, he was so busy learning the ways and customs of men. First he had to wear a cloth round him, which annoyed him horribly; ...
In illustrations and movies however Mowgli is often wearing a loincloth.
The nudity of Mowgli has nothing to do with sexuality (there are of course some exceptions)