When I run this could and click on the dialog box my radiobuttons do not become selected like intended

package edu.elon.cs.mobile;

import edu.elon.cs.mobile.R; import edu.elon.cs.mobile.R.id; import edu.elon.cs.mobile.R.layout; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; import android.text.Editable; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.RadioButton; import android.widget.TextView; import android.widget.Toast;

public class PTCalculator extends Activity{

private RadioButton maleRadioButton;
private RadioButton femaleRadioButton;

private EditText ageEdit;
private EditText pushUpsEdit;
private EditText sitUpsEdit;
private EditText mileMinEdit;
private EditText mileSecEdit;

private Button calculate;

private TextView score;

protected AlertDialog genderAlert;
private int currScore;

private int age;
private int sitUps;
private int runTime;
private int pushUps;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.pt);
    maleRadioButton = (RadioButton) findViewById(R.id.male);
    femaleRadioButton = (RadioButton) findViewById(R.id.female);

    ageEdit = (EditText) findViewById(R.id.ageEdit);
    pushUpsEdit = (EditText) findViewById(R.id.pushupEdit);
    sitUpsEdit = (EditText) findViewById(R.id.situpEdit);
    mileMinEdit = (EditText) findViewById(R.id.minEdit);
    mileSecEdit = (EditText) findViewById(R.id.secEdit);

    calculate = (Button) findViewById(R.id.calculateButton);
    calculate.setOnClickListener(calculateButtonListener);

    score = (TextView) findViewById(R.id.scoreView);

    genderAlert = makeGenderDialog().create();
}


private OnClickListener calculateButtonListener = new OnClickListener() {

    @Override
    public void onClick(View arg0) {
        age = (Integer.parseInt(ageEdit.getText().toString()));
        pushUps = (Integer.parseInt(pushUpsEdit.getText().toString()));
        sitUps = (Integer.parseInt(sitUpsEdit.getText().toString()));

        int min = (Integer.parseInt(mileMinEdit.getText().toString())*60);
        int sec = (Integer.parseInt(mileSecEdit.getText().toString()));
        runTime = min + sec;

        if(maleRadioButton.isChecked()){
            MalePTTest mPTTest = new MalePTTest(age, pushUps, sitUps, runTime);
            currScore = mPTTest.malePTScore();
            score.setText((Integer.toString(currScore)));

        }else if(femaleRadioButton.isChecked()){ 
            FemalePTTest fPTTest = new FemalePTTest(age, pushUps, sitUps, runTime);
            currScore = fPTTest.femalePTScore();
            score.setText((Integer.toString(currScore)));

        }else
            genderAlert.show();
    }
};

public AlertDialog.Builder makeGenderDialog(){

    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage("Select a Gender")
    .setCancelable(false)

    .setPositiveButton("Female", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            femaleRadioButton.setSelected(true);
            FemalePTTest fPTTest = new FemalePTTest(age, pushUps, sitUps, runTime);
            currScore = fPTTest.femalePTScore();
            score.setText((Integer.toString(currScore)));
        }
    })
    .setNegativeButton("Male", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            maleRadioButton.setSelected(true);
            MalePTTest mPTTest = new MalePTTest(age, pushUps, sitUps, runTime);
            currScore = mPTTest.malePTScore();
            score.setText((Integer.toString(currScore)));
        }
    });

    return builder;
}

}

Any suggestions?