Male or Female?

As is the rule for most species, males are generally bigger and stronger than females.  Males mark their territory and females come into heat.  As to their behavior and temperament, it is an individual matter.  There are "rules of thumb" one may elude to, but as to specific facts, again, it is an individual matter.  Example:  Generally, if a female dog is already in the home, it would be better to introduce a male and vice versa.  Two of the same sex dog can sometimes become an issue.  However, many variables influence this "rule of thumb".

What do the different colors look like?

The bull terrier comes in many different colors.  They are: black brindle, brindle, red (smut), tri-colored, and white.  Colored dogs may have various white markings while white dogs may have various colored markings.  Below are the colors with an example of each.

The pup to the right is brindle. Brindle is a color that is a mixture of brown, black, and red hairs. Brindle dogs vary in shades, according to what color hair is dominant.    Unlike this pup, some colored dogs have nearly no white on them.  Almost all colored dogs have a white tipped tail, the rest of their white markings will vary.
This pup is an example of a white bull terrier. White bull terriers can come with any number of colored markings in black or brown on their head.  Usually white bull terriers have pigment spots on their body as they mature underneath their white coat.               This pup sports a beautiful brindle eye patch. Eye patches and eye spots come in an array of sizes and colors.   If you are planning on showing your white bull terrier, there should not be any colored hair on the body of the dog beyond the head.  Skin pigment spots are acceptable in the show ring.
This pup illustrates what a tri-colored bull terrier looks like.  Tri-colored dogs are black with tan points on their face, legs, and belly. White markings are usually on the face, neck, paws, and belly.               Here is a tri-colored dog with very little white.
Black Brindle bull terriers are black bodied dogs that have some brindling on their face and legs. Remember, brindle is a color that is a mixture of brown, black, and red hairs.  They have the typical white markings that vary. The dog to the right has some brindle on his face and a little brindle on his legs.  Notice how his brindle markings are different from the tri-color's solid tan markings.
Red bull terriers are also called Smut.  Their color ranges from tan to red.  We do not have any pictures available of this color at this time.	Picture Pending