knabiĉo

Etymology
From.

Noun

 * 1)  boy

Usage notes
The neologistic suffix is controversial, but even among its proponents the word knabiĉo is usually not recommended. The word traditionally already means “boy” even without the addition of the masculine suffix, making the suffix redundant.

Users of the term think the redundancy of is preferable to the asymmetry between the forms  and.

See also Gender reform in Esperanto and its section Masculine suffixes on Wikipedia, and the article on -iĉ- in Esperanto.