There is an article on sexing found on http://www.caudata.org/cc/
Basically you want to look for a swallon bump between the back legs during breeding season. It's hard to sex outside of breeding season, and sometimes with some species even during breeding season it can be very difficult.
>>Hi, i recently bought 2 firebelly newts at an expo and they look great, what i wanted to know was how can i tell if its a male or female.....i mean is it the same as checkin for other pets?......any way i will put some pics up...tell me wat u think of them
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Hope my opinions help,
Rob