And how did you make those "check boxes"
Seems like radio buttons--which do not as readily allow the user to select both Yes AND No values would make more sense.
But HOW did you do that? Did you define two fields and then what? did you use the Inspector to format them as check boxes?
What Value list Did you specify?
I would add a single field to the layout, use the inspector to specify a radio button format and use a custom values value list of "Yes"; "No" custom values. That way if the user first clicks Yes, then clicks No, only the No value will be selected unless they hold down the shift key while clicking the radio buttons. (There's a way to prevent that, but first things first.)
You can make this work with check boxes, but in computer interface design, radio buttons are supposed to indicate a case where only one value can be selected and check boxes are supposed to indicate that multiple values can be selected. This "rule" is often broken, but it's one I prefer not to break.