JSFiddle - React, Tailwind, and code Playground

HTML

<form action="/Health/Create?clientId=1&amp;clientReferenceNumber=rtg" method="post">    <fieldset>
        <legend>Health</legend>

        <input data-val="true" data-val-number="The field Int32 must be a number." data-val-required="The Int32 field is required." id="ClientId" name="ClientId" type="hidden" value="1" />
        
        <div class="editor-label">
            <label for="Disability">Disability</label>
        </div>
        <div class="editor-field">
           <select name="Disability" id="Disability">
                <option value="None">None</option>
                <option value="Physical">Physical</option>
                <option value="Mental">Mental</option>
                <option value="Learning">Learning</option>
                <option value="Sensory">Sensory</option>
                <option value="Drugs">Drugs</option>
                <option value="Alcohol">Alcohol</option>
                <option value="Other">Other</option>
            </select>
            <span class="field-validation-valid" data-valmsg-for="Disability" data-valmsg-replace="true"></span>
        </div>

        <div class="editor-label">
            <label for="Pregnant">Pregnant</label>
        </div>
        <div class="editor-field">
            <input class="check-box" data-val="true" data-val-required="The Pregnant field is required." id="Pregnant" name="Pregnant" type="checkbox" value="true" /><input name="Pregnant" type="hidden" value="false" />
            <span class="field-validation-valid" data-valmsg-for="Pregnant" data-valmsg-replace="true"></span>
        </div>

        <div class="editor-label dueDate">
            <label for="DueDate">Due Date</label>
        </div>
        <div class="editor-field dueDate">
            <input class="datepicker" data-val="true" data-val-date="The field Due Date must be a date." id="DueDate" name="DueDate" type="text" value="" /> 
            <span class="field-validation-valid" data-valmsg-for="DueDate"...

JavaScript

$(function () {
            if (!$('#Pregnant').is(':checked'))
                $('.dueDate').hide();
            $('#Pregnant').change(function () {
                if ($('#Pregnant').is(':checked')) {
                    $('.dueDate').show();
                } else {
                    $('#DueDate').val('');
                    $('.dueDate').hide();
                }
            });
  });