<form
      [formGroup]="signUpForm"
      (ngSubmit)="onSubmit()">

        <div class="radio">
          <div *ngFor="let gender of genderValues">
            <label>
              <input
                formControlName="gender"
                value="{{gender}}"
                type="radio"
                name="gender"
                (change)="radioChangeHandler($event)">
              {{gender === 'Male' ? 'Hombre' : 'Mujer'}}
            </label>
          </div>
        </div>
</form>

signUpForm: FormGroup;
genderValues = ['Male', ' Female'];

this.signUpForm = this.formBuilder.group({
      // Asigno un gender como default
      gender: [this.genderValues[0], [
        Validators.required
      ]]
    });

radioChangeHandler(event: any) {
    // Guardar value nuevo
    this.gender.setValue(event.target.value);
    console.log(this.gender.value);
  }