If one parent has Attention Deficit Disorder, what is the chance that
each child born from this parent will have ADD?

Whether ADD (or ADHD) has a genetic cause, direct or indirect, has not
yet been scientifically proven beyond any doubt. Since your question
implies, but does not specify, inheritance via sexual reproduction,
the question is not easily answered. Perhaps a clarification as to
whether you are looking for an answer from a nurture or nature angle
would help.

Just for your information, there was in the late 80's, a group of
doctors who were attempting to publicize their study which showed a
high correlation between those who as children had many ear
infections, thus receiving many doses of antibiotics.

The antibiotics allegedly destroy the natural flora and fauna in the
intestines, which are known to produce many desirable by products.  In
their absence, yeast infections move in, and the yeast allegedly
produce many chemicals, which the group believe is the true cause of
ADD.  Note they believe sugar causes the yeast to grow very fast, and
would by their theory produce large amounts of chemicals at that time.

I have no real opinion, but my ADD son did indeed have many ear
infections and receieved a lot of antibiotics. All parents where I
worked also admitted their ADD kids were the same.

My son, now 29 and in medical school, drinks acidophilus milk, which
would help fill in the intestines, and claims he feels better with
this sort of milk. Yogurt also would help.

Just last month, on a genealogy forum a man said he was ADD, and I
told him this tale. He admitted he had many ear infections, and was
going to look into it.

Note that these doctors were indeed M.D.'s, not quack doctors. I
assume google would point you at them.  They claimed to be able to
make referrals to other doctors who would treat for yeast infections.

For your information only.

google for:  yeast ADHD infection ear intestines

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