JSFiddle - React, Tailwind, and code Playground

HTML

<label>Male
   <input type="radio" name="IsMale" value="1" data-bind="checked:IsMale"/>
</label> 
<label>Female
   <input type="radio" name="IsMale" value="0" data-bind="checked:IsMale"/>
</label>
<div data-bind="text: !!+IsMale()"/>

JavaScript

var vm = {
    IsMale: ko.observable(false)    
};
ko.applyBindings(vm);
//vm.IsMale(!!+vm.IsMale());
//console.log(!!+vm.IsMale());