<div class="female">
    <input type="radio" id="female" name="sex" />
    <label for="female">女</label></div><div class="male">                
    <input type="radio" id="male" name="sex" />
    <label for="male">男</label></div>

input[type="radio"] + label::before {
    content: "\a0"; /*不换行空格*/
    display: inline-block;
    vertical-align: middle;
    font-size: 18px;
    width: 1em;
    height: 1em;
    margin-right: .4em;
    border-radius: 50%;
    border: 1px solid #01cd78;
    text-indent: .15em;
    line-height: 1; 
}

input[type="radio"]:checked + label::before {
    background-color: #01cd78;
    background-clip: content-box;
    padding: .2em;
}

input[type="radio"] {
    position: absolute;
    clip: rect(0, 0, 0, 0);
}