He's all boy...

What a weird phrase. "He's all boy." I just heard someone say that about their 18 month-old son. I know I've probably said this, but never really thought about it what it implies.

What would make an 18 month old boy less than all boy? Would someone say..."He's only semi-boy" if he picked up a doll once at daycare? What are the qualifications for "all boy"?

Just something to ponder.