What is the significance of the "checked" attribute in a radio button in PHP?

The "checked" attribute in a radio button in PHP is used to pre-select a radio button option by default. This is useful when you want one of the radio buttons to be already selected when the form loads. To use the "checked" attribute, you simply add it to the desired radio button input tag with the value set to "checked".

<input type="radio" name="gender" value="male" checked> Male
<input type="radio" name="gender" value="female"> Female