To make a family medical chart, I take a
piece of paper and list my relatives, like

© 2006
What does a therapist do?  
The first time, the therapist will try to get to know you and your
background. Some  people are disappointed if the first session is only
about that. Nothing scary happens, not that I've ever heard about anyway.
Family Medical Chart
I usually bring a simple family medical chart to a therapist. It's not as
complicated as it may sound. It saves time with the therapist and since they
charge by the hour, it might be worth doing.
Then I go back and for each, put
the name, dates of birth and
death (if applicable), and health
highlights (see below)
Health highlights might be heart trouble, diabetes, cataracts, Down's,
Asperger's, whatever. It might be useful to note other diseases, such as
alcohol and gambling. Don't spend forever on it - it's not a research project,
just a little summary to save time on your first meeting with a therapist.
There is such a thing as researching your own family, but that's a huge
exercise that you'd get guidance for. The kind of thing that I'm talking about
would take only one line per relative.
Give to Therapist?
There seems to be some importance (but I don't know why)
attached to whether you give the chart to the therapist to keep, or to
read and give right back to you, or for you to read it to therapist.
Give it some thought before you go, decide which is best for you.