<p>Since we figured out that there were boys, and there were girls, pregnancy has been a time when people have tried to guess which pregnancy would produce which baby. Long before there was the science of genetics, before we could tell the X carrying sperm from the Y carrying sperm, there were schemes devised to tell us whether or not you would have one or the other. </p><p>This has lead to some really interesting methods of trying to figure it out. Nowadays we simply use <a href="https://www.verywellfamily.com/ultrasound-photos-of-girls-and-boys-in-pregnancy-2758367" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="1" rel="nofollow">ultrasounds, usually done around the midpoint of pregnancy</a>. This doesn&#39;t mean <a href="https://www.verywellfamily.com/how-soon-can-ultrasound-tell-sex-of-baby-2758976" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="2" rel="nofollow">we don&#39;t want to know sooner</a>.</p><p>Legend has it that this chart was found in an ancient tomb in China and is supposedly based on the Chinese lunar calendar. By using the mother&#39;s age at conception and the month of conception, supposedly you can determine with 100% accuracy if your baby is a boy or a girl. <em>(There are two charts with ages 36-45 listed below the first chart.)</em></p><p><a href="https://www.verywellfamily.com/fun-ways-to-find-out-the-sex-of-your-baby-2758372" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="3" rel="nofollow">Be sure to check out the other ways to tell if you&#39;re having a girl or boy!</a></p><table border="1" cellpadding="5" cellspacing="0"><tbody><tr><td colspan="29"><p><strong>Mom&#39;s Age at Conception</strong></p></td></tr><tr><td><strong>Month of<br/>Conception</strong></td><td>18</td><td>19</td><td>20</td><td>21</td><td>22</td><td>23</td><td>24</td><td>25</td><td>26</td><td>27</td><td>28</td><td>29</td><td>30</td><td>31</td><td>32</td><td>33</td><td>34</td><td>35</td></tr><tr><td>January</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>B</td><td>G</td><td>B</td><td>B</td></tr><tr><td>February</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td></tr><tr><td>March</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>B</td><td>B</td><td>B</td><td>G</td></tr><tr><td>April</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>B</td><td>G</td><td>G</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td></tr><tr><td>May</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td></tr><tr><td>June</td><td>B</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>B</td><td>B</td><td>B</td><td>G</td><td>G</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td></tr><tr><td>July</td><td>B</td><td>B</td><td>B</td><td>G</td><td>G</td><td>B</td><td>B</td><td>G</td><td>G</td><td>B</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td></tr><tr><td>August</td><td>B</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>B</td><td>B</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td></tr><tr><td>September</td><td>B</td><td>B</td><td>B</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td></tr><tr><td>October</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td><td>G</td></tr><tr><td>November</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td><td>G</td><td>G</td><td>B</td><td>B</td></tr><tr><td>December</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>B</td><td>B</td><td>B</td><td>B</td><td>B</td></tr></tbody></table><p> </p><table border="1" cellpadding="5" cellspacing="0"><tbody><tr><td colspan="29"><p><strong>Mom&#39;s Age at Conception</strong></p></td></tr><tr><td><strong>Month of<br/>Conception</strong></td><td>36</td><td>37</td><td>38</td><td>39</td><td>40</td><td>41</td><td>42</td><td>43</td><td>44</td><td>45</td></tr><tr><td>January</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td></tr><tr><td>February</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>G</td></tr><tr><td>March</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td></tr><tr><td>April</td><td>G</td><td>B</td><td>B</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td></tr><tr><td>May</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td></tr><tr><td>June</td><td>G</td><td>B</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td></tr><tr><td>July</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td></tr><tr><td>August</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td></tr><tr><td>September</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>B</td></tr><tr><td>October</td><td>B</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td></tr><tr><td>November</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td><td>B</td><td>G</td><td>B</td></tr><tr><td>December</td><td>B</td><td>B</td><td>G</td><td>G</td><td>G</td><td>B</td><td>G</td><td>B</td><td>G</td><td>B</td></tr></tbody></table><p> </p><p>These are designed as a way to have fun and pass the time while pregnant. Certainly, there are those who will have a reading that is true, and those who won&#39;t. Please keep this in mind as you read the chart and see the answer. Some mothers use these in the <a href="https://www.verywellfamily.com/pregnancy-your-week-by-week-guide-4159265" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="4" rel="nofollow">first trimester</a> before they <a href="https://www.verywellfamily.com/early-gender-prediction-kits-2758839" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="5" rel="nofollow">know the sex of their baby</a>, and some in countries other than the United States, aren&#39;t allowed to find out the sex of their baby and will play these games the entire pregnancy. Here&#39;s to hoping!</p>