example.html

<fieldset>
  <legend id="dob__legend">
    <span class="errors">Feb 30th does not exist</span>
    <span class="form-question">When did you enter this world?</span>
    <span class="text--help">Like, born or whatever</span>
  </legend>
  <label id="dob_month__label" for="dob_month" class="sr-only">Month</label>
  <select name="dob[month]" id="dob_month" aria-labelledby="dob__legend dob_month__label">
    <option value="1">January</option>
    ...
  </select>
  <label id="dob_day__label" for="dob_day" class="sr-only">Day</label>
  <select name="dob[day]" id="dob_day" aria-labelledby="dob__legend dob_day__label">
    <option value="1">1</option>
    ...
  </select>
  <label id="dob_day__label" for="dob_year" class="sr-only">Year</label>
  <select name="dob[year]" id="dob_year" aria-labelledby="dob__legend dob_year__label">
    <option value="1900">1900</option>
    ...
  </select>
</fieldset>