I'd expect all of the gingko in bonsai nurseries to be male. I think this is because we westerners have preferred, over time, not to deal with the fruit which can create a mess and has a 'distinctive' odour.
I think you'd have to look hard to find a female (fruiting) variety like Queen of Fruits.
http://kwanten.home.xs4all.nl/ is a great source of information on Gingko from which I have copied this ....
Gender: the tree is dioecious, male and female trees are separate. The sex chromosomes (XX females and XY males, just like humans) are difficult to distinguish, so the tree's gender is not easily classified.
The pollen and ovules grow on the short spurts, very seldom on the leaves (Ohatsuki). Occasionally both genders are found on the same tree.
After a hot summer or grown in a warm sunny position the tree produces them more reliably.
The female tree has an abundance of ovules in pairs on stalks each containing an egg cell, looking very green on the start but turning into greenish-yellow followed by orange and brown.
They look like cherries. It takes about 20-35 years before they appear for the first time in spring. Catkin-like pollen cones (microsporangia) containing the sperms on the male tree also grow on short shoots in spring (also after about 20-35 years) and the pollination usually takes place via the wind. The female tree can carry seeds without pollination (sterile). Variations in the cycle of pollination, fertilization and seed abscission in Ginkgo are mainly due to the latitude and the local climate of the region in which the tree is growing.
When the ovules are fertilized they develop into yellowish, plumlike seeds about 2,5 cm (1 inch) long, consisting of a large "nut" (the size of an almond) with a fleshy outer layer. The actual fertilization of the seed by free swimming sperm occurs mostly on the tree (read more here).
The seed has a silvery shine ("silver apricot/nut"). The ripened fleshy seedcoat when falling on the ground and decaying has a 'disagreeable' odour (like rancid butter) as a result of the presence of butyric (butanoic) acid, a common byproduct of many plants and animals (the same compound that in small quantities is used in perfumes) and can be very messy, making the female trees unfortunately less popular for planting in pedestrian areas. This period doesn't last long however and much 'trouble' can be prevented by cleaning up the fallen seeds regularly etc. In countries like Korea, Japan and China female trees are preferred because the people appreciate the nuts! More information about the 'smell' of the seeds: click here.
The propagation can also be done by cuttings (the best way to ensure the gender) or by grafting a female branch onto a male plant or visa versa.
