Why is the drop-down list not working in the administrative module?

Question

Django

Can't select value in dropdown box

from django.db import models

gender_choices = [
  (1, "man"),
  (2, "woman")
]

class User(models.Model):
  name = models.CharField(max_length = 100)
  mail = models.CharField(max_length = 100)
  gender = models.CharField(max_length = 1, choices = gender_choices, default = 1)  #с этим полем что то не так
  age = models.IntegerField()