hello every body
what is the way to get the selected checkbox value on server side?

this is my code:

<ext:RadioGroup runat="server" ID="rdGender" FieldLabel="الجنس">
                        <Items>
                            <ext:Radio InputValue="M" runat="server" ID="rdMale" BoxLabel="ذكر"></ext:Radio>
                            <ext:Radio InputValue="F" runat="server" ID="rdFemale" BoxLabel="أنثى"></ext:Radio>
                        </Items>
                    </ext:RadioGroup>