Whether or not you choose to find out the sex of your baby at your 20-week scan or not is a BIG topic, and one that divides opinion straight down the middle.
But, for some of you, there was no choice in having the sex of your baby as a surprise: you just 'knew' if you were having a boy or a girl.
OK, OK, we know it's a 50/50 chance you'd get it right - but when we asked our mums about this just knowing (perhaps mother's instinct) on Facebook, you had lots to say.
The ones who 'knew'
"I wanted to find out the sex of my baby - but I knew I was having a girl before I was told officially," Claire A tells us.
"Did lots of research into nub theory and my gut instinct told me it was a girl." Karen M agrees with the mother's instinct aspect, saying: "I knew each of my babies' gender before I was even told at their scans - a mother's instinct is great."
And Rachel B was so confident she started buying everything up in a particular colour: "I was so adamant with my last I was having a boy.
"I actually told everyone I was having a boy and chose a name and bought blue clothes - and I was right!" Phew ?
The ones who thought they knew
On the other hand, we had a few mums who were pretty confident they 'knew' what they were having - only to be thrown a big old reality curveball.
"I knew I was having a girl with both my pregnancies...especially second time round, the feeling was so strong!" reveals Abi C. "I now have two gorgeous BOYS ? ? "
"I was convinced I was having a boy, as was my partner," Tara B tells us. "We wanted to find out at the 20-week scan and both our jaws dropped when we were told it was 99% certainly a girl.
"That 99% became 100% when she was born - so my 'mother's instinct' was totally off that time at least!"
The one who knew and was told she was wrong - but was right
"I thought boy second time round as it 'felt' different and the nausea, whilst still crippling, felt different," recalls Vicki C.
"The scan revealed another girl... so I bought pink stuff, my first daughter's clothes sorted and washed to be used again, baby name chosen. Then a little boy lands on my living room floor ?.
"Hard to trust instinct when two sonographers tell you baby is definitely a girl!? "
What do you think?
Did you 'know' the sex of your baby before you had any scans? Tell us in the comments below or over on Facebook