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Research Article

Fetal sex determination: by female?

Maihua Hou, Xinzheng Lu, Hongmei Zhang

Department of Dermatology, Nanjing Medical University, China

Correspondence: Maihua Hou, Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China, Tel 861-377-663-5881, Email

  • Volume 1 Issue 1
  • Received: June 10, 2016
  • Published: June 20, 2016
Current explanation about fetal sex determination is based on the biological genetic research

We have come a long way in our understanding of sexual determination since 355 BC. In those days, Aristotle suggested that the difference between the two sexes was due to the heat of semen at the time of copulation: hot semen generated males, whereas cold semen made females.1 Following the rediscovery of Mendel’s paper in 1900,2 the 20th century became the century of genetics. Wilson3 found that in different species of insects, spermatocytes differed either in the presence or absence of one chromosome, or in the size of one of the chromosome pairs. Stevens4 investigated both sexes of the common mealworm, Tenebrio molitor, and found that in males, but not females, one chromosome was smaller than the others, and she concluded that this chromosome must be responsible for the determination of male sex. The smaller chromosome became known as “Y”, the larger one as “X”,5 and both as “sex chromosomes”.6 The data suggested that the role of chromosomes were in sex determination. By the end of the end of the first quarter century, Morgan7 proposed that the genetic evidence showed that human sex-determining mechanisms must be either XX/XY or XX/XO. The discovery of sex-chromosome anomalies, notably XXY in Klinfelter’s syndrome8 and a single X and no Y in Turner’s syndrome9 suggested that the Y chromosome performs an important function in the development of the human male.  An important involvement of sex-determining region Y gene (SRY) in male sexual development is not in doubt, but no direct target has been discovered, and the expectation of finding the pathway from gene to phenotype has not so far been fulfilled.10

The found based on the Chinese lunar calendar

In addition to the Hsia or Chinese Solar Calendar, the Chinese have a Chinese Lunar Calendar. It is based on the moon’s rotation around the earth which takes approximately 29.53059days. Twelve lunar months add up to 354.36708 days and is not equal to one solar year of 365.242199 days. To solve this problem, the Chinese added an addition month in 7 out of every 19 years. The additional month takes the name of the month before and is known as a leap month. The first lunar month is not called January. Instead it is simply called the 1st Month. The second month is called the 2nd Month and so on until the 12th Month. Each lunar month can have either 29 or 30 days. We are here present other way to predict fetal sex according to Chinese lunar calendar. According to this way, we investigated the people who were born before 2010, the mothers’ year of birth and the month of conception were determined, and these dates were converted into their lunar equivalents, found that 72% people coincide with the rules: the children were males with their mother were single ages (Chinese ages, such as 21, 23, 25 years old) and the month of conception were double month (Chinese lunar calendar, such as 2nd, 4th, 6th, 8th, 10th and 12th), or their mothers were double ages (such as 22, 24, 26 years old) and the month of conception were single month (such as 1st, 3rd, 5th, 7th, 9th, 11th month); on the contrary, the children were females. However, 28% people of our investigated don’t coincide with the rules, of them 44% were born in the years which contained leap months. Maybe after the first leap month a woman’s child gender becomes against the rules, next leap month it will come back to the rules.

Undoubtedly, the results made us being shocked, it is completely against the genetic rules and it clearly suggests that sex determination is by female. We can almost predict the gender of one mother’s baby through the female’s year of birth. Maybe we should notice another phenomenon that the moon’s rotation around the earth which takes approximately 29.53059 days, which is the basis of Chinese lunar Calendar, almost equal to a menstrual cycle of 28 days. Moreover, the Chinese name of menstruation is associated with “month”, or ancient Chinese had the idea about sex determination by female? There is always a Chinese folk “sex determination by female”, but no one to demonstrate its truth.

The gender of offspring keeping with the female age isn’t purely accidental, it means that the ovulation has its regular pattern. We speculate the ovulation is done by left and right ovary alternatively. It is supposed, at normal situation, the fetal from the eggs of the other side should become always males, the eggs in another side should become females; the women who only had children with same gender may be due to the function of one side of ovary was not active or Salpingemphraxis. Small part of people can’t coincide with the rules is due to the menstrual cycle is not completely equal to a lunar month, for example, if a female has menstrual cycle of 35 years, she will have 456 times of ovulation (if every menstrual cycle is 28days), but there are 433 Chinese lunar months (contained 13 leap months) at the period of 35years, so if the period of menstrual cycle is exact 29.53059 days, the gender of her child will keep with the rules completely. From our investigation table, we almost predict the gender of a woman’s next child if we know her first child’s gender and the period of her menstrual cycle. We still can’t explain why most people coincide with these rule and not opposed rules, maybe the ovulation is associated with the Law of universal gravitation, which is more dominant in the right or left ovary. Moreover, the Chinese lunar calendar is exactly based on the moon’s rotation around the earth.

Contrast to the research on the Y chromosomes, the research about eggs is not certain to carry weight. Maybe the chromosomes of XX and XY from female and male in sexual determination are not a simple number model, gene expression of eggs keep to be elucidated. Because many research reported environmental sex determination ((usually temperature-dependent sex determination) occur in a viviparous reptile,11,12 we propose that a special gene in the eggs or the special environment factor in the human ovary to determinate whether the expression of Y chromosomes. However, Warm-blooded human, compared with cold-blooded the reptile, must have more complicated environmental sex determination.

Concluding thoughts

Our investigation found that fetal sex determination probably was associated with the female. Our hypothesis suggests that eggs or the special environment factor in the ovary to determinate whether the expression of Y chromosomes. Though we provide correlative evidence in support of our hypothesis, direct experimental evidence for our hypothesis is still lacking. We hope that presentation of this hypothesis article will stimulate new investigations into this putative relationship. The sex determination is an ancient theme which ever perplexes human for many years. There is a right answer for this question may be good news for human. Moreover, the sex determination by female is in keep with the natural rules because the development process of eggs is much more complicatedly than the development process of semen.



Conflict of interest

Author declares that there is no conflict of interest.

Citation: Hou M, Lu X, Zhang H. Fetal sex determination: by female? Author J. 2016;1(1):3‒4.

Creative Commons License   © 2016 Hou et al. This article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work even commercially.