<p>
<input type="radio" value="male" name="gender" [ngModel]="user.gender" > Male
<input type="radio" value="female" name="gender" [ngModel]="user.gender" > Female
</p>
<p>
<input type="checkbox" name="tc" [ngModel]="user.isTCAccepted" >
</p>
Try to specify value attributes. And do not forget that in case of radio buttons Model is not supposed to contain boolean value but should contain radio specific values like:
<input type="radio" name="food" value="beef" [(ngModel)]="myFood"> Beef
<input type="radio" name="food" value="lamb" [(ngModel)]="myFood"> Lamb
<input type="radio" name="food" value="fish" [(ngModel)]="myFood"> Fish