Is there a way to have an OR in the required?

Is there a way to have an OR in the required? For example, if they fill out their father's name, I would require a cell number OR a work number.

Hello,

You can set your form to have a condition that sets a field as required or enabled based on a previous field or reference field. 

Then simply add two conditions that shall hide or disable the other field if one of them is filled. Meaning -- (1st condition) if mobile number is filled, hide the office number. (2nd condition) If office number is filled, hide mobile number. Here is a sample screenshot of the conditions on how it may appear:

Check out this form in action following the conditions above: https://form.jotform.com/63407352147958 

You can check this guide for the information: https://www.jotform.com/help/367-How-to-Make-a-Field-Required-Based-on-User-s-Answer

If you have questions, please let us know.

Thanks.