从给出的代码中还不清楚Javascript/jQuery函数autosave实际上是如何被调用的，也不清楚这是否是PHP的问题，所以下面的内容可能会引起兴趣，也可能不会引起兴趣。在这一小段Javascript中没有jQuery-我不使用它，所以会对它造成伤害，但这是简单的普通Javascript。
对HTML的一个小修改（不是绝对必要的，但是语法上是正确的）是使用section来定义每个单选按钮组-这具有允许我们容易地计算页面上的单选按钮组的数目并且将其与checked单选按钮的数目进行比较的好处-当它们相同时，ajax函数将被发送-从而确保所有的单选按钮都包含在POST请求中，这意味着PHP可以正常更新数据库。

const d=document;

// 1 radio button from each of these MUST be checked before ajax request is sent
let oSections=d.querySelectorAll('section');

d.addEventListener('change',e=>{
  if( e.target instanceof HTMLInputElement && e.target.type=='radio' ){
    // Find ALL checked radio buttons
    let col=d.querySelectorAll('section [type="radio"]:checked');
    
    if( col.length === oSections.length ){
      // 1 radio from EACH section is now checked, create
      // the FormData payload to send via AJAX to the server.
      let fd=new FormData();
      col.forEach(n=>fd.set(n.name,n.value));
      
      // Send the request
      fetch( 'fetch1.php', { method:'post',body:fd } )
        .then(r=>r.text())
        .then(data=>{
          d.querySelector('#post_id').value=data;
          d.querySelector('#autosave').textContent='Data saved';
        })
        .catch(alert)
    }
  }
});

section{
  border:1px dotted grey;
  margin:0.25rem;
  padding:0.5rem
}
h6{
  margin:0 0 1rem 0;
}

<section class="col-md-6 mb-4">
  <h6 class="mb-2 pb-1 " style="font-size: 20px;">Gender:</h6>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="gender" type="radio" name="gender" value="Female" />Female
    </label>
  </div>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="gender" type="radio" name="gender" value="Male" />Male
    </label>
  </div>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="gender" type="radio" name="gender" value="Other" />Other
    </label>
  </div>
</section>

<section class="col-md-6 mb-4">
  <h6 class="mb-2 pb-1 " style="font-size: 20px;">Skin Color:</h6>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="scolor" type="radio" name="s_color" value="Green" />Green
    </label>
  </div>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="scolor" type="radio" name="s_color" value="Orange" />Orange
    </label>
  </div>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="scolor" type="radio" name="s_color" value="Purple" />Purple
    </label>
  </div>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="scolor" type="radio" name="s_color" value="Red" />Red
    </label>
  </div>
  <div class="form-check form-check-inline">
    <label class="form-check-label">
      <input class="scolor" type="radio" name="s_color" value="Gold" />Gold
    </label>
  </div>
</section>