I have problem in dropDownButton in Flutter. Can anyone help me?

Question

here is my code of dropDownButton.I'm trying to making select GenderList dropDownButton but when I assign variable selectedGender to value of dropDownButton it's hide hint text and default select first index value Male. I want this output

But I'm getting this output when i assign selectedGender variable type int to value in dropDownButton

Here is my code when I comment on the value then it shows a hint text let's see my code below.

import'package:flutter/material.dart';



class DropDownButton extends StatefulWidget {
  const DropDownButton({Key? key}) : super(key: key);

  @override
  State<DropDownButton> createState() => _DropDownButtonState();
}

class _DropDownButtonState extends State<DropDownButton> {

  
  List<DropdownMenuItem<int>> genderList=[];


  void loadGenderlist(){
    genderList=[];

    genderList.add(const DropdownMenuItem(
        child: Text('Male'),
        value: 0,));

    genderList.add(const DropdownMenuItem(
      child: Text('Female'),
      value: 1,));

    genderList.add(const DropdownMenuItem(
      child: Text('Other'),
      value: 2,));

  }


  String selectval = "United Kingdom";
  int selectedGender = 0;


  @override
  Widget build(BuildContext context) {
    loadGenderlist();
    return Scaffold(
        appBar: AppBar(
            title: Text("Form Validation with All Controls"),
            backgroundColor: Colors.redAccent
        ),
        body: SafeArea(
          child: ListView(
            children: [
              DecoratedBox(
                decoration: BoxDecoration(
                  color: Colors.green,
                  border: Border.all(color: Colors.black38,width: 3)
                ),
                child: DropdownButton(
                    hint: Text("Select Gender"),
                    items: genderList,
                    //value: selectedGender,
                    onChanged: (value){
                      setState(() {
                        selectedGender =int.parse(value.toString()) ;
                      });
                    },
                  underline: Container(),
                ),
              )      
            ],
          ),
        )
    );
  }
}

I want this output: