Dear Dr. Gott: With no access to a suspected birth father for DNA testing, how can it be proved who someone's father is? Testing with siblings is not an option. If a person has access to a suspected birth father's blood relatives, could a test be conducted with them to prove paternity? If so, what is the test called? Which relatives would be the best to test? Would we need a doctor's order? How much would the test cost? Is there a special facility other than a hospital that could perform the test? Any advice you have would be greatly appreciated. Thank you.

Reply: Paternity, to the best of my knowledge, is best proven with the father's DNA; however, there is a test known as the grandparentage test that can prove whether the individual is related to the suspected birth father's family. If there is only one son, then it is proof, but issues arise if there is more than one son because the test cannot differentiate between them to determine which one is the father. It can, at least, establish some grounds.

There are other tests, such as sibling tests, that can be used to determine whether two individuals are siblings, and if one has an established paternity, it can be used as proof of paternity for the other.

As for the cost of testing, it depends on the type of test used, the laboratory and other factors, such as whether there is more than one potential father. A company known as DNA Diagnostics Center (www.DNACenter.com) offers two types of testing: home and legal. Home DNA tests are used for personal use only. Legal testing follows a strict chain of custody that can be used in legal paternity, custody or support cases.

Whatever the case may be, options are available. Perhaps a meeting with a social worker, lawyer or therapist familiar with these issues would be helpful. These professionals may be able to explain the process, help with finding a reputable laboratory or testing facility, and handle the outcome in regards to child support, custody and other situations that may arise.

Dear Dr. Gott: I write in response to a recent article about a woman with a burning mouth. The same thing happened to my late mother-in-law about 20 years ago. She suffered for about a year and saw several dentists and doctors without help. One day, I noticed my mouth started burning. It took me a few days to realise that I had changed to toothpaste that had baking soda and whiteners in it. After switching back to plain toothpaste without all the additives, we both found relief. I hope this simple thing will help someone else.

Reply: I am printing your letter because it offers a simple possible solution for burning mouth. Toothpastes today not only clean the teeth and freshen the breath; they also whiten teeth, prevent cavities and so much more. In order to do this, the manufacturers are continually fiddling with the formula and adding more substances. For those with sensitivities or allergies, such as you and your mother-in-law, this can cause annoying, painful symptoms.

To provide related information, I am sending you a copy of my Health Report 'Allergies'. Other readers who would like a copy should send a self-addressed stamped number ten envelope and a $2 cheque or money order to Newsletter, PO Box 167, Wickliffe, OH 44092. Be sure to mention the title or print an order form off my website at www.AskDrGottMD.com.

Dr. Peter H. Gott is a retired physician and the author of several books, including 'Live Longer, Live Better', 'Dr. Gott's No Flour, No Sugar Diet' and 'Dr. Gott's No Flour, No Sugar Cookbook', which are available at most bookstores or online.