Ok I had to google for the frog sex facts-
[4. How do I tell the sex of my frog or toad?

Sexing frogs depends on the species. There are a number of tropical species that are dimorphic in regards to color, with the males being more colorful than females. In Minnesota, Bullfrogs and Green Frog males have larger eardrums than females. In some species males will have enlarged thumbs. Most good field guides will provide descriptions of the differences.

Under certain conditions, some frogs can change their sex! Check it out:
http://newton.dep.anl.gov/askasci/bio99/bio99128.htm ]

[4. Will frogs and toads breed with other species?
Not successfully. Some males are nonselective of mates and will mount other males, which will give a warning noise for the other to release its grasp. ]

and some other stuff

[1. What is the difference between frogs and toads?
Frogs have:
smooth or slimy skin
strong, long legs
webbed hind feet
two bulging eyes
lay eggs in clusters
a group of frogs is called an
ARMY of frogs

Toads have:
warty and dry skin
stubby bodies with short hind legs
paratoid glands behind eyes
lay eggs in long chains
a group of toads is called a
KNOT of toads]

http://cgee.hamline.edu/frogs/science/faq1.html#anatomy