This article studies the relationship between sex ratio at Birth (males per females) of USA and the Chinese Baby Gender Prediction Chart to help American women to choose desired gender for their next babies. This involves the usage of Chinese Lunar Calendar. We recommend people to use new Revised Chinese Zodiac-Lunar Months.
Years ago scientists form different countries had researched what might influence the sex ratio at birth. Their studies reported that the seasons and regions affect the sex ratio at birth. US National Center for Biotechnology Information published a study of The Association between Season of Pregnancy and Birth-Sex among Chinese in 2014. After reviewing that research data and comparing with Chinese baby gender chart, we published an article of Chinese Gender Predictor Chart versus China sex ratio at Birth relationship. We discovered that Chinese Baby Gender Predictor Chart is somewhat accurate but not precise in China. But this doesn't mean Chinese Baby Gender Predictor Chart is accurate for other countries. Therefore, we want to analyze the birth data of USA sex ratio at birth to see if the Chinese Baby Gender Chart is accurate for USA women.
Many families in the world prefer boy babies. According to the 2017 data bank from United Nations Population Division shows the sex ratio of male births per female births is 1.073. The average sex ratio from 1997 to 2017 is about 1.075. The birth data at US Centers for Disease Control (CDC), 1977663 baby boys and 1887091 baby girls born in 2017. The US sex ratio between males and females is 1.048. That indicates that girls like to be born in USA.
USA Sex Ratio Statistic Survey Data and Chinese Baby Gender Chart
The National Center for Health Statistics at US Centers for Disease Control (CDC) and Prevention provides good US birth data including, birthplace, birthday, gender, race, mother age and father age. We interest in pregnancy months and baby genders relationships.
We downloaded the US natality data from 2007 to 2017, and then calculated the sex ratio at birth. There are 44,300,538 baby records, 21,631,917 girls and 22,668,621 boys. The sex ratio at birth is 1.0479. We break down it into monthly sex ratio in the following.
|US Birth Data 2007-2017|
April, May, June and July have higher sex ratios. That means more boys were born in April, May, June and July in USA. Pregnancy lasts for about 280 days or 40 weeks. It's about 9 months. The conception months in July, August, September and October are favorable to have a baby boy.
Review Chinese Baby Gender Chart
The chart below is the Chinese Baby Gender Statistic Chart. The age in the chart is woman's Chinese age at conception. The month in the chart is the month of the conception. The chart is from Ching Dynasty. People think the month should be the Chinese Lunar Month. For the prediction, blue is for boy and pink is for girl.
|Age||Woman's Conception Chinese Lunar Month|
We are interested which conception months have better chances to have a baby boy. Therefore, we sum up the boy counts for each month.
|Lunar Month||Near Zodiac||Proximity Month||Boy Counts|
If we count for boy blue box in the Prediction Chart for all month columns, we find that January, February, March, April and September have higher boy counts.
Pregnant months in the spring have better chance to have a baby boy in China. Pregnant months in the autumn have better chance to have a baby boy in USA. This tells us that Chinese Baby Gender Prediction Chart doesn't work for USA women.
California, New York and Texas Sex Ratio at Birth
The sex ratio of male births per female births varies from country to country. According to United Nations Statistics Division, the sex ratio at China is 1.15, India is 1.107, Armenia 1.129, Azerbaijan 1.125 and Vietnam is 1.097. The sex ratio at birth of USA was 1.0479 in 2017. That implies the sex ratios at birth are been affected by geographical regions. Therefore, we want to take at look on the sex ratios at birth in California, New York and Texas. We simply list out the sex ratios more than 1.05.
|Sex Ratio of CA, NY & TX 2007-2017|
The monthly sex ratios of California, New York and Texas are slight difference. But April, May, June and July are the common months in three different states. The higher monthly sex ratios at US west coast, east coast and south region don't have too much difference.
The Trend of Sex Ratio at Birth
Next, we want to know if monthly sex ratios are the same for the newer generation. The following sex ratios at birth are from 2015-2017. We show only the sex ratios greater than 1.05.
|US Sex Ratio Birth Data 2015-2017|
May and June are still the higher sex ratio months. Therefore, August and September are months most likely to conceive baby with boy gender.
Mother Ages and Chinese Baby Gender Chart
The Chinese Baby Gender Chart shows the women's age is the factor to affect the baby gender. Therefore, we want to check the sex ratio statistic data to see any connection with women's ages.
|US Birth Data 2007-2017|
|Woman Age||Sex Ratio||Woman Age||Sex Ratio|
It's obvious that there is no connection between mother ages and sex ratios in USA. Several other studies have examined relationship between the age of mother or father to the birth sex ratio. They said mother age has no statistically significant impact on birth sex ratio. But younger fathers have higher chance to have male babies.
Recommend Zodiac-Lunar Months for Baby Gender Prediction Chart
Another issue in the Baby Gender Chart is the pregnant month. Most people think the pregnant months should use the Chinese Lunar Calendar. But Chinese Lunar Calendar needs extra lunar month every three years in order to synchronize the cycle of the sun. That means Chinese lunar year has 13 lunar months every three years. The Baby Gender Chart doesn't mention about the leap months. Some people have question about we should use the Chinese Zodiac (Stem-Branch) Months instead of the lunar months.
Therefore, we compromise the Chinese Zodiac Months with Chinese Lunar Months into new Zodiac-Lunar Months the following chart. The days of Zodiac-Lunar Months must in both of lunar month and its corresponding Zodiac month. We strongly recommend using Zodiac-Lunar Months for the Chinese Baby Gender Prediction Chart.