proper planning/design in c#

What i am achieving is good design in c# and not interested in how to in code. I always have these kind of scenerios in code.

Lets say i have to hold an employee which has 5 properties which can be Age,Sex,height,area and married.
I then need to hold several employees and would like to do queries on employees e.g show me employees who are married for example.

Also say for an employee there is another property say isAdminUser. This isAdminUser is a property or method which checks permission on Active Directory . I dont need code to query Active directory but i assume i have an extra class called cActiveDir somehow. ??????

thanks kindly.