I have a basic form, but if I a user wants to add additional information (like another registration), is there a way a trigger can be created so it will automatically add another form for the user to fill in data?

For example I have a basic form:
First Name:
Last Name:
Child's First Name:
Child's Last Name:
Age:
Email:
Phone:
Address:
City:
State:
Zip:

(add additional child?) <trigger here>

If the user doesn't click on the trigger to add an additional child, then user can proceed to finish filling out other data:

Payment information:
Emergency/Medical Information:
Terms and Conditions

I also would like for an automated calculation to be applied for every child that is added to the registration based upon the form being filled out. For example, if they fill in the first form for one child, then a hidden field will automatically calculate the given total at the bottom of the form. If the user adds another child based upon filling in another form, then that additional charge will be posted within the total. Can something like this be done automatically or does this require another trigger?

Thank you.