The subject of The Child's Brain is a nude young man, seen from the waist up, who is standing in back of a table with his eyes closed.

[1] The painting depicts a nude young man with a mix of both masculine and feminine features (the feminine being especially prominent in the lack of body hair or defined musculature, the long eyelashes and the finely groomed eyebrows) standing behind a table which blocks our view of him below the waist.

The man himself is likely a younger version of the figure of Dionysos who appears in later works by de Chirico, such as The Phantom.

This can be interpreted as the man being faced with the terror of castration which can be found in the psychological work of Sigmund Freud.

It is at this time that the male child develops an obsession with his genitals, that leads to the realization of gender difference and a fear of castration.