Start them right!
I almost screwed this one up. After much talking and debating, mywife said if we were going to have guns in the house, she wanted to know how to use them. Cool.
First trip to the range, the first gun I let her shoot was my H&K .40. At 25 yards. She was less than thrilled with the experience. When I explained it was her first time, the Range Master let us go to 7 yards. Much better results, and much more fun. On the way home, we stopped at the gun store and ordered a Ruger Mk II. It's HER gun, and I get to borrow it sometime. She enjoys it much more than the .40. But, she can hit with the 22, the 40, or our 20 Ga out to 25 yards, and feels safe with any of them.
In fact, she's been on bed rest for the last 6 months for a difficult pregnancy. Now she says she is going to leave me home alone so she can go shooting.