[ad_1] <br><br>An economist says controlling for early illness cuts the estimated birth-order earnings gap roughly in half. <br>[ad_2] <br> <br> <br> <br><a href="https://www.newsnationnow.com/health/smarter-elder-child-study-germs/" style="font-size: 12px;color:#D5DBDB" target="_blank">Source link </a>