id say male on the right and females on the left,but from my understanding they r hard to sex,but males apparently will be bigger headed,there r a couple of good breeding articles in herpetofauna and monitor magazine,herpetofauna volume 29 number 2 and monitor vol 15 number 1,hope that helps,if they r ok together im sure they will show u what sex they r if the breed for u,good luck with those little beasties,keep us posted on there progress