Hamster testicles...

[POLAR WHITES]

He looks male

[daphnephoebe]

If you've got a glass to put him into to have a closer look you can also tell by looking at his actual anatomy.

You'll notice two small dots to the bottom of his body. One will be his anus, the other will either be his manly part, or her female part.

Female bits sit very close together, you can see hardly any gap between the two.
Males have a noticeable gap, normally about 1/4 inch.

Males bits do drop in warmer weather, and as already pointed out. They like to sit on them like cushions.

[POLAR WHITES]

If you do want to change sand, children's play sand is good to use can be dried in the oven and it's dust free.

[xFluffyHamsterx]

That's exactly wat p@h said to me! I found out it was a boy instead after noticing the huge balls on it!!