Create Content Fields "on the fly"

Hi,

I'm building my user profiles with cck and the content_profile module. To explain my problem/question here's a little example:

The user profile containes fields to collect information about himself and his children (birthday, school and gender for each child). Because the quantity of children differ from family to family I don't know how many content fields are needed to be created in the first place (five children, six children … 20 children?).

Until now, all user information are stored in one content type (information about the user himself and the user's childrens information). I'm thinking about to separate the children's content fields from the user profile information and create a new content type for the children's information. Then a user could click "create a new child" such as creating a new blog entry. So he could enter as many information about his children as he needs I don't need to fear users with unbelievable amount of children ;).

Another way I thought about is to create content fields for 20 children (just to be safe!) so there would be 60 content fields (birthday, school and gender for each of the 20 children). Then I would utilize jQuery to hide all those fields and create an "add button" to unhide those fields (each click on the "add button" shows 3 more fields: birthday, school, gender).

My third option would involve an incredible amount of time to search the whole net for a module that would give me the "add button" on the edit page of a user's profile. Everytime a user clicks on the "add button" three content fields are created "on the fly". No extra content type, no pre-created content fields.

Which way is the best to go? I've really no idea.

Thanks for any help :)