@chiabotu, maybe you could do it as outlined in the image shared below through the calculation column instead of the default column:
In the survey tab of your XLSForm:

In the choices tab of your XLSForm:

Data entry screen as seen in Enketo: when nothing is selected in a select one question
Data entry screen as seen in Enketo: when male is selected in a select one question
Data entry screen as seen in Enketo: when female is selected in a select one question
Reference XLSForm:
Default Response (Jr choice name).xlsx (11.2 KB)



