No I am not getting into the kinky side of life, and no this is not an ADULT content site. I have written this section only because of the high number of questions being asked by the novice breeders.

What sex is my Canary; Boy or Girl, Hen or Cock.
It is very difficult to tell the gender of a canary at first glance and many an expert has come to grief by getting it wrong.
Remember that during the moult and winter the cock bird sings less and sometimes not at all.
What I will not be covering in this section is Sex-linked which means in certain circumstances you can tell the gender by the colouring of the parents. This is particularly significant for Cinnamon.

Hen / Girl
The certain way to tell a Hen Canary is if it lays an egg, then there is no doubt. Some breeders even put a pink split ring on the opposite leg to the closed ring to give the Hen a permanent marker.
If your Hen sings its a good chance its not a hen, read on.
Cock / Boy
There is no certain way to say a cock is a cock, however if the Fife Canary sings with gusto you have a 99.999’% chance of being a cock. Very occasionally you will get a Hen bird that sings but, the song is usually weak and broken.
The best way I have found to get a cock bird to sing, is in spring, place the bird in a small cage, in a sheltered sunny spot; usually a healthy cock bird will sing within minutes.
The problem you have, is that if it does not sing it does not make it a Hen as some cocks may either be unfit or just stubborn. Luckily the Fife Canary cock usually sings.

The sex organs of the canary do not have the distinct differences as with mammals and this method is only reliable in the Breeding season when the bird is fit and ready to breed.
You blow away the feathers of the vent
Cock bird the skin leading up to the vent is elongated and quite prominent and the vent itself is still narrow.
Hen bird the skin leading up to the vent is flat or only just raised and the vent itself is rounder and flatter.
I must stress that the differences are not always evident and only occur at the height of the breeding season.

If your loaded with money and nothing better to spend it, on you can take your bird to a vet with a suitable ultra sound and he can tell you within minutes what sex.
Or you can have a DNA test done which will prove gender
But this in my opinion is going too far. If you watch your canary in the breeding season you will soon know.