My husband has CBVAD, and possibly atypical Cystic Fibrosis. What are the statistics of people with CBVAD and Cystic Fibrosis and/or Carrier? Also, what is the likelihood our son will have CBVAD?

-A curious adult Cystic fibrosis (CF) happens in about 1 in 3500 live births for Northern American whites, 1 in 9,500 for Hispanics, and less than 1 in 15,000 for Africans and Asians. In some parts of England, the number goes as high as 1 in 377 live births. What this translates to is around 70,000 people worldwide dealing with CF.

How true is the saying? The apple does not fall far from the tree. Please give a comparison of human and plant DNA. A picture of plant and human DNA sequences would be nice, so that I can see the similarities.

-A curious adult from Utah

January 14, 2005

In some ways, the saying is very true. The building blocks and shape of DNA molecules in humans, plants and every living thing is the same -- we all have the famous A, C, G, and T's. It's the order of these letters that makes us different.

Some of these A, C, G, and T's code for genes, which in turn code for proteins. Proteins are the things in our body that do all of the work. They are involved in activities like digesting food, thinking and breathing.

Not surprisingly, the proteins that do the same things in plants and animals have similar DNA sequences. However, even when the proteins are very similar, when and where in the body they do their job can be very different.

I am a 31 year old ultrasound technologist. Three years ago I lost a baby girl when I was 5 months pregnant. I was scanning myself at 13wks and discovered the cystic hygroma with hydrops. I had an amnio a few weeks later which was normal. About

-A curious adult from Illinois Too much blood clotting in the mother can cause cystic hygromas to develop in fetuses. The Factor V Leiden mutation you describe definitely leads to increased blood clotting. There are some reports that the MTHFR A1298C can also lead to increased blood clots, but this is much less well established.

Is the tendency for anger genetic?

-A high school student from California

January 6, 2005

Wow, this one was a toughie! What we are really talking about here is getting angry easily. Some work in behavioral genetics suggests that this trait can be inherited.

As anyone who has kids can tell you, there are some parts of personality that seem to be hard wired. Scientists who have studied this have found that one of the strongest inherited genetic traits is something they've called temperament.

What if some people had a version of a gene that resulted in a stronger chemical being made? Or more of the chemical being made in a certain situation? Or a receptor that needs less chemical to work? They'd all get angry more easily.

Maybe a concrete example will make this easier to understand. Let's say Bob gets mad when he tries to program his DVD player but Sam doesn't. Let's say it takes 100 of a "normal" chemical to generate an anger response.

I have heard that the MTHFR mutation can affect whether a woman has a baby with Down syndrome or not. I have also heard that taking folic acid can help. Does the MTHFR mutation also affect men? Can they benefit from extra folic acid as well?

-A curious adult from Malta

July 19, 2007

The MTHFR mutation you are talking about is likely to cause problems for pregnant women. You mention Down syndrome.

But it can also lead to an increased risk of miscarriage. And it can also be an increased risk for having kids with birth defects that involve the brain and/or spine.

I have asthma and I was wondering if I would ever grow out of it and also if when I have kids if they would have it as well?

-A high school student from Colorado About half of all kids with asthma no longer have it by the time they grow up. Even some adults outgrow it later in life, particularly if they have a mild case of asthma. Asthma does tend to run in families. If your parents had asthma, you are more likely to have asthma too. What this means is that there is increased risk of your children developing asthma. How much?

My father had ankylosing spondylitis. I am 53 years old and have scoliosis and some back pain. Recently I had SI joint X-rays that were normal. What are the odds of me having ankylosing spondylitis?

-A curious adult from New Mexico When ankylosing spondylitis (AS) runs in your family, the chances of you having AS are about 20% if you're under age 40 and very low if you're over 40. X-rays are the most accurate way to diagnose AS because having the gene for AS does not necessarily mean that you'll have the disease. People who are over 40 with normal x-rays have a very low risk of developing AS. I can see why you'd be worried about AS, since people with the condition have episodes of back pain to severe, back stiffness, loss of motion and deformity.

Hello- I have a 1 year old son. I would love to have a daughter next. Is there anything that you know of that I can do to push the odds of having a girl???

-A curious adult from New York People have probably been trying to pick the sex of their kids since time began. For example, in the Middle Ages, men who wanted a boy sometimes had their left testicle removed. This was because people believed that the right testicle made "boy" sperm and the left made "girl" sperm.