I question the need for this age children to use a computer for genealogy. If you search "genealogy for children" on the web, you will get plenty of ideas on introducing them to the concepts using processes that will be creative and fun for them.
There is something to be said for having them sit down with paper and drawing out a tree with themselves, parents, and grandparents. Children don't gain the ability to do abstract reasoning until 11-13 years usually, so unless they know their great grandparents, even these won't mean much to them.
If you are determined to do this, a moderately able high-school age programmer should be able to create such a program for you in BASIC, or even web-based, in a weekend.
I suspect that the market for such a simple program would not attract a professional programmer to expend the time required.
Nick