Vuejs: How to recover ID of specific checkbox

I'm totally new to Vue, so dumb question time!

I have a series of checkboxes on the page. Their status ie checked or unchecked are pulled from L8 and applied to the form. It works, but I hope I have done that part correctly! Great. When a user changes the status of a checkbox, say from checked to unchecked I need to uniquely identify that specific child_id. What I have at the moment grabs ALL the checkbox statuses. Not ideal, as I will then use axios to post that specific child_id back to the server, and I don't want to send the whole array every time a user changes one check box. So, this what I have so far:

From the template

<tbody v-for="child in Children">
          <tr>
            <td class="col-4"><a :href="'/getchild/'+ child.child_id">{{child.childFirstName}}</a></td>
            <td class="col-4"> {{child.childLastName}}</td>
            <td class="col-4">
              <div class="custom-control custom-switch">
                <input type="checkbox" class="custom-control-input" ref="child.child_id" :id="child.child_id" :value="child.child_id" v-model="child.status" @change="Checked" >
                <label class="custom-control-label" v-bind:for="child.child_id">Absent / Present</label>
              </div>
            </td>
          </tr>
          </tbody>

From the script:

<script>
      export default {
        data: function () {
          return {
           Children: []
          }
        },
        mounted() {
        this.loadChildren();
        },

        methods:{
          Checked:function(){
            console.log(this.$refs)
          },

          loadChildren:function (){
            axios.get('/api/allChildren')
            .then((response)=>{this.Children = response.data.data;
            })
            .catch(function (error){
                console.log(error);
              }
             );
          }
        }
    }
    </script>

Many thanks for your help!!