The last time I traveled with a child (3 y/o) was in September. They asked, can she stand still for the scan? I said I didn't know, and they waved us through the metal detector rather than the X-ray machine. The TSA were very helpful in CRP and DFW. I don't know how it would go today, when the TSA seems to be doubling down on their 'everyone gets scanned' policy and there is more tension between TSA and the general public.
In general, give yourself plenty of time. There is a specific FT forum that may have more info:
Travel with Children.
Give us your airport and people can be more specific. If your airport has checkpoints where you can avoid the x-ray naked scanners, you should definitely try to use those.
If were pregnant, I would not choose to get an x-ray for any reason except for medical necessity. The earlier in the pregnancy, the higher the risk to the fetus.
From the
Canadian government:
Fetuses are more susceptable than adults to the damaging effects of x-rays, partly because their cells are rapidly dividing and growing into specialized cells and tissues. If x-rays cause changes in these cells, there is a slightly increased chance of birth defects or certain illnesses, such as leukemia, later in life. However, most birth defects and childhood diseases are not attributed to exposure to any known harmful agent during pregnancy.
Damage to fetal cells may result in miscarriage, birth defects, or mental impairment, depending on the amount of radiation and the stage of pregnancy. The risks are higher during the first three months of pregnancy (first trimester). It is important to note that most of these effects do not usually occur below 100 mGy - more radiation than three pelvic CT scans or 20 abdominal x-rays.
There is an increased risk of childhood cancer from DNA damage regardless of when in pregnancy the radiation occurred. The risk is believed to be proportional to the amount of radiation, i.e. the smaller the amount of radiation, the smaller the risk of cancer. Most studies show no increase in childhood cancer from small amounts of radiation. However, one study identifies the chance of a childhood cancer from abdominal x-rays (in the 10 mGy range) at about one in 1,000 births. In comparison, the chance of a childhood cancer in the general population is about two to three in 1,000 births.
The airport x-rays give a dose of about 1 uSv, and this is 1/10,000 of the 10 mGy dose referenced in the article. So probably harmless, assuming the machine is properly calibrated. But why take any chance?