Week 20: Boy or Girl

Finally, the pregnancy is half over. Amber is starting to get a bit bigger from her 100lb (46 kg) self. She needs new clothes but doesn’t like the maternity clothes available. I’ll leave it to her to write the details of her travails.

Now is the time to find out if we are having a boy or a girl. Amber has always wanted a boy. I have an adverserial side to my personality which means that I am hoping for a girl. It’s fun to argue about the sex of the fetus. One interesting aspect of our discussions is that Amber seems to want a most feminine boy while I am looking forward to a tomboyish girl. Perverse, isn’t it?

To answer the big question of what are we having, we turn to our friend, the Internet. It turns out there are many, many ways to predict the sex of your unborn child.

Let’s first use the Chinese Calendar method. Amber was 30 at the time of conception which was in November. Checking the table, we find out it’s going to be a boy.

People also say that girls have heartbeats faster than boys. Our fetus’s has consistently been greater than 140, so girl ties boy 1—1. But all my enthusiasm was dashed though by this guy who did some scientific study showing that fetal heart rate does not predict sex at all.

Instead of boring you with each of these old wives’ tales, let’s go directly to the results. Taking this quiz, we found out that there’s a 66% chance that we are going to have a girl. Yay, I win!

Enough of the old wives’ tales. Let’s find out how we can scientifically find out the gender of the fetus. There seem to be three main methods:

  1. Chorionic Villus Sampling (CVS) is generally only performed if there is a high risk of genetic abnormalities as there is a 4% chance of miscariage as a result of this test.
  2. Amniocentisis is also similar and is generally not recommended unless the Alpha-fetoprotein test comes out positive.
  3. Since the other two options are out, the only one we are left with is the ultrasound. An ultrasound is not a very good way of finding the gender of the baby. We know several people who got it wrong. The most common mistake is “we can’t see a penis, so it’s a girl.” The accuracy depends on several factors like the position/pose of the fetus, gestational age, technician’s ability, etc.

We were hoping our doctor would make a recording of the ultrasound video at our next monthly appointment. May be if we played it like 100 times, we could figure out if it’s a girl or a boy. Plus I could use my mad image analysis skills to write a penis detection algorithm. Unfortunately, they don’t do video recordings.

UPDATE: Here is some info about the accuracy of ultrasound for determining the gender of a fetus.