Create a New Data Definition (Go to -> Control Panel -> Dynamic Data Lists -> Add -> Select -> Add)
Add a Text item (Name) and a Radio item with two options (Sex: male, female). Set the required to Yes.
Save this Data Definition, and the Dynamic Data List which contains it.
In the Dynamic data Lists list click on this, then on Add Record.
You see the next:
The (Required) label is redundant after each options of the radio item.