My husband is HIV+. I am not. We have 2 healthy children and would like one more, but I want to be tested to determine why I have not become infected before I take the risk. I have read a little about the chemokine receptor (lacking one or a faulty one) preventing infection. How does one go about getting tested for this type of thing?

I am not a medical doctor and do not know a lot about this, but yes, there is such a thing as a specific genetic factor that is believed to be protective from HIV transmission. However, my understanding is that it is relatively rare and also not definitive. There are a number of possible reasons that people do not become infected when exposed to HIV. Besides genetic susceptibility, they include the health of the infected person, the general health of the uninfected partner, the viral strain and viral load of the HIV+ person, the immune system of the uninfected person, the specific sex behaviors and condition of the genital organs (e.g., presence or absence of any sores or ulcers), etc. etc.

I recommend that you speak directly with a physician experienced in HIV disease and explore the issues and options for you and your husband regarding your desire to have another child.