Most can be sexed just looking for the spurs of the male. With neonates they will be small and the color may hide them. At your age you may need a magnifieing glass.lol just kidding.
I don't know how many scales exactly but it is obvious after you,ve probed a femal, the probe will seemingly dissapear on the male. I would have to guess they are males. I would also say that a female neonate will probe somewhere around 3/16" - vrs around 1/2" on some males. Just what I've noticed.
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Steve Perry
North Idaho.

