Pregnant women are taking the selfie craze to a new level by posting pictures of their 12-week scan online for friends to predict the sex.
A poll by parenting site Netmums found a third of parents had uploaded scans to social media sites like Twitter and Facebook for other users to guess whether their baby will be a boy or a girl.
A further fifth put pictures on parenting sites asking for others' opinions.
The fastest-growing scan analysis trend is the 'nub theory', which uses the 12-week scan picture to see what angle the nub - a small lump where the genitals will develop - is pointing.
The theory, used by one in ten, says if the baby's nub points up by 30 degrees or more it is a boy.
If it is less than 30 degrees it's a girl, with seven out of ten claiming the technique accurately predicted their baby's sex.
Meanwhile, six per cent said they tried the 'skull theory', with a square skull and jaw said to be a baby boy and a rounder skull a girl.
But seven out of ten expectant mums use the more traditional method to guess the sex of their baby by the shape of their bump.
If it is wider it is said to predict a girl, but if the bump protrudes more it could be a boy.
A third analysed their food cravings and half even tried to predict the gender by how sick they felt.
More unusual methods included a twelfth who looked at the size and shape of their breasts, and a fifth who used a Chinese Gender Calculator to guess the sex using conception date and the mother's age.
还有一些不太寻常的方法，包括有十二分之一的人会看孕妇乳房的大小和形状，有五分之一的人会用中国式胎儿性别预测器（Chinese Gender Calculator）来检测，这种方法主要以怀孕日期和母亲年龄为依据。
Overall, one in eight couples admitted they had tried to 'sway' the gender of their child to get their desired sex.
This included more than a third making love in a specific position.
Over a fifth had sex at set times of the month, with making love on the day of ovulation believed to be more likely to create a boy.
But if couples stop having sex three to four days before ovulation their efforts are more likely to produce a girl.
One in 16 couples also timed sex to match phases of the moon.
Many tried a 'gender diet', with one in seven mothers eating a diet said to influence the sex, along with a twelfth making their partner follow suit.
It is claimed a low calorie diet with lots of leafy green veg and fruit makes it more likely to have a girl, with brooding mothers-to-be skipping breakfast.
But for a boy, they should have a high calorie diet packed with potassium rich foods such as bananas, red meat and salty food. And breakfast is a must.
Netmums, which polled a total of 2,227 women, found 11 per cent now get early tests to find out the sex of the baby before the 20 week scan.
A further eight per cent booked a high-powered 14-week scan which is the first time the baby's gender is usually clear.
Netmums Managing Director Rimi Atwal, said: 'Selfies at 10 weeks gestation may seem strange but young mums use selfies at every step of their lives, so sharing scan pictures is the natural way to involve friends, families and even strangers in their pregnancy.
'The popularity of the Nub Theory has created a huge community online with mums-to-be sharing others joy and supporting them as they go through the special time of pregnancy.'