Is there a way to have a radio group be laid out horizontally?

You can also set this programmatically:

myRadioGroup.setOrientation(LinearLayout.HORIZONTAL);

Add android:orientation="horizontal" to RadioGroup tag:

<RadioGroup
   android:id="@+id/radioSex"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content" 
   android:orientation='horizontal'>