1. Navigate to the user's profile, and select the three dots "..." in the upper right hand corner, and choose Member settings.
2. Then in the pop up, simply toggle on (or off) the button to hide the age for the user. When age is hidden, only the Month and Day of Birth will display on their profile, the calendar, the Birthdays widget and the Family Tree.
Note: Users can also hide their age themselves from their personal settings.