CHOICES_GENDER = [('m', 'man'), ('w', 'woman')]

class Student(models.Model):
    ...
   gender = models.CharField(max_length=1, choices=CHOICES_GENDER)

class StudentAddForm(forms.ModelForm):
    ...    
    gender = forms.ChoiceField(widget=forms.RadioSelect(attrs={'class': 'radio-control'}), 
                               choices=CHOICES_GENDER, initial='m'),
    ...

    <form action="" method="post" novalidate>
    {% csrf_token %}
    <table>
        {{ form.as_table }}
        <tr>
            <td>&nbsp;</td>
            <td><input type="submit" value="Submit"></td>
        </tr>
    </table>
    </form>

Article.objects.filter(relatad__last_name)