Watch pit bulls and parolees on animal planet. They are great dogs if treated right.
To counter the starting article: It was on the news the other day about a pit bull that saved his family from a fire. He wouldn't leave until all of the family was out of the house. He was badly burned.
A girl walking down the road with her pit. Man pulls up and tries to kidnap her. She and the pit are fine. The cops are looking for someone with several holes in his leg. I have heard many of these stories.

On the surface, your idea of checking the DNA sounds good. however, there are so many genes involved in temperament, not a single gene for any behavior in either man of dog. You would have to find all the genes for fear aggression, which are different from those which modify reactive to noise, territorial, food protective, toy hording aggression. The genes may be located in different areas for different breeds, so the crosses might have new locations, not like either parent. Studies to find the gene for primary lense luxation in terriers took years and thousands of dollars and it is only a single gene, no modifiers. Way too much of a task. then you have to add envirorment, epilepsy, brain tumors, diabetes as causes for aggression and you can see what an impossible task it really is. Suggestion for anyone buying a dog. go to a reliable breeder, handle their adult dogs, watch the dogs at dog shows and performance events, check the pedigrees, then train and socialize the dog well, feed it well and make sure that if you bought it as a house dog, not a working dog for livestock or hunting, it lives in the house with you. Make sure the breeder will help you any way they can, and get references from people who have purchased dogs from that person. A bargain dog seldom really is a bargain.

Dogs that are bred to fight other dogs are not necessarily people aggressive. However, unsocialized dogs, untrained and locked in a room may very well become very aggressive. Of course dogs of this size have extremely powerful jaws and can easily kill someone who is old, or a baby. However, the American Staffordshire terrier, the close relative of the "pit bull" can have a delightful temperament if properly raised and trained. Most of the dogs labeled "pit bulls" are mixes of a number of breeds, often with some Am Staff and mastiff in them, and bred to be aggressive enough to protect the drugs, usually meth or coke, the owner has. Pound per pound most Yorkshire terriers are more aggressive, but they are small enough to pick up and lock in a cage if they get aggressive. Many people who have "pit bulls"
are using then for purposes that require the dogs be aggressive and dangerous. Those people should not have dogs,period. Never ban a breed just have better laws that mandate dogs that seriously harm a person be put down. For instance the "pit bull" that ripped off half a child's face last week, should be euthanized as soon as his rabies observation period is up. Instead a group of moron PETA people are whining and collecting money to save the dog. Donations should be made toward the child's surgery not the damn dogs life.
One of the problems with banning a breed of dog is that most animal control officers or policemen couldn't tell the difference between a French Bulldog and a "Pit bull".

Contrary to popular hysteria, pit bulls who've been socialized and are from healthy stock (which is to say, not inbred to make them extra aggressive) are no more dangerous than any other breed of dog.

No idea about the bloodline of the dogs that killed the woman (but have my suspitions), but dogs locked up in a bedroom obviously were never socialized.

Rottweilers are often considered dangerous, as well, but the same applies to them as does pitbulls (and every other breed)...socialization and good breeding makes for loving, lovable dogs, as my son's three Rotties, my 2 Great Danes, my Grandmother's Irish Wolfhound and my daughter's assorted "yappers" prove time and again.

This often happens when humans start breeding for characteristics. Designer dogs! Take the Lacy, this dog will be able to survive in any situation. They have been bred to take down large animals, as big as bulls. They can survive eating scrub grass and go for days without water. Now they are great dogs, but in 20 years they too may become a hazard to humans and in particular small children. I like mutts. Most of them are a combination of many breeds. I do love animals, and my heart breaks when I turn away a pit bull. But, my family has to come above my rescue efforts.

Thank you for the insight and thought you put into your comment.