What is the nub theory — and should you trust it?

The nub is the small genital tubercle you can sometimes see on a first-trimester scan. Folklore says a nub pointing up like a clock at 12 is more boy, and a nub parallel to the spine is more girl.

It is the same idea as old wives looking at a bump and declaring ‘all out front, must be a boy’. People love a pattern. Scientists want a sagittal plane, a trained operator, and a later scan.

Our peek looks at nub angle among other cues — skull, lie, how crowded the frame is. It will also refuse a photo that is not a fetal ultrasound. Confidence is a vibe, not a lab report.

Keep the print, keep the fun, and let the 20-week appointment have the last word if you need certainty.