Baby gender predictor - boy or girl?

Boy or girl? It's the question everyone wants to know the answer to. You may have heard of all the old wives' tales, or tried gender prediction methods that involve odd and even days and the numbers of the year. They're fun but they don't have the facts to back them up. We've looked at the scientific studies into what influences the sex of a baby. We've rounded up the most useful and used them to create our gender predictor.

Please note: while this tool is based on the available science, many of the studies are very small scale and they all show only slight changes in the likelihood of having a boy or girl. Also, some studies carry more weight than others, so your result may say one sex, even though more of your answers point to the other. Finally, whatever result you get, treat it with caution. And hold off painting the nursery blue or pink just yet!

---

Thank you for taking the quiz! Here are your results:

You have -4 correct answers.

Based on your answers, the research suggests that you are slightly more likely to have a boy!

Are you over 35?

• Yes

• This answer suggests it could be either a boy or a girl
  No

• ---

  EXPLANATION: There is some evidence that the older you are when you conceive your baby, the more likely you are to have a girl. The sex of the baby is partly controlled by the level of the hormone gonadotropin, and this declines with age.

  ---

Were you living with the father of your baby when you conceived?

• This answer suggests it could be a boy
  Yes

• No

• ---

  EXPLANATION: One very large study of 86,000 people shows a figure of 51.5 per cent male births for those living with a spouse or partner before the child's conception or birth, and 49.9 per cent male births reported by respondents who were not.

  ---

Is the father of your baby over 40?

• Yes

• This answer suggests it could be a boy or a girl
  No

• ---

  EXPLANATION: It seems that the older a dad is the less likely the male sperm are to fertilise the egg and the female sperm win the race. The latest evidence is that the quality of sperm does deteriorate with age and older men produce fewer male sperm.

  ---

How many children do you already have?

• This answer suggests it could be a boy or a girl
  None

• One
• Two or more

• ---

  EXPLANATION: The research here shows that the more children you have, the more likely you are to have a girl. This may be linked to the fact that the more pregnancies you have, the higher your levels of the hormone gonadotropin. This seems to be linked to a higher chance of having a girl.

  ---

Were you eating a high or low calorie diet when you became pregnant?

• High

• This answer suggests either a boy or a girl
  Medium

• Low

• ---

  EXPLANATION: A study divided 740 British women into groups according to their calorie intake. 56 per cent of the women who had the highest energy intake had boys. 45 per cent of the women who had the lowest energy intake had boys. The average calorie intake for women who had boys was 2,413. The average calorie intake for women who had girls was 2,283. It has been suggested that our bodies only invest in boys (who are more fragile and statistically less likely to survive) when food is abundant. In times of famine or low food production we "play safe" with more robust girls. Remember, whether you're having a boy or a girl, a healthy diet is very important before and during pregnancy.

  ---

Does the father of your baby work in any of these occupations: airline pilot, deep sea diver, submariner, timber mill worker, flour mill worker?

• Yes

• This answer suggests either a boy or a girl
  No

• ---

  EXPLANATION: Some studies have looked at the father's occupation and the ratio of boys and girls. Occupations that involve stress or pollutants seem to lead to more girls. But these are small-scale studies that have only looked at certain occupations.

  ---

Were you under stress before you became pregnant?

• This answer suggests it could be a boy
  Yes

• No

• ---

  EXPLANATION: We know more boys are born at times of stress, such as after wars, and research carried out so far seems to confirm this. One theory is that the mother's high stress levels lead to increases in both testosterone and cortisol. This may lead to changes in the egg, which makes it easier for male sperm to penetrate. Just how this happens no one is sure, but there is much mystery still about the moment of conception.

  ---

Did you conceive after having your ovulation induced hormonally?

• This answer suggests it could be a girl
  Yes

• No

• ---

  EXPLANATION: Studies carried out among women who used hormones, such as Clomid, to induce ovulation show that you are slightly more likely to have a girl if artificial hormones are involved.

  ---

In your pregnancy, have you suffered from severe morning sickness (hyperemesis gravidarum)?

• This answer suggests either a boy or a girl
  No

• Yes, I had no treatment or was treated at home
• Yes, I was admitted to hospital for treatment

• ---

  EXPLANATION:

  ---

Were you born in a tropical climate and living in a tropical climate when you conceived? (Only answer yes if the answer is yes to both parts.)

• Yes

• This answer suggests it could be either a boy or a girl
  No

• ---

  EXPLANATION: A global survey of birth data showed that more girls are born in the tropics than anywhere else in the world. Scientists are not sure why. One possible theory is that it is the effect of the hormone melatonin, which has been shown to cause changes in the reproductive systems of animals in response to the length of the day. More females are born when the days are longer. Or it could be that high temperature alters the survival of male or female sperm in semen.