Briefs facts for kids
For male briefs, before 2000s, briefs often came with hard elastic waistband. This would cause stretch marks, and this was eventually replaced by the soft elastic waistband. However, hard elastic waistbands are still found on generic store brand underwear (that save consumer and manufacturing costs by not being fashion forward).
Images for kids
A figure skater wears a costume with attached briefs under the skirt
Briefs Facts for Kids. Kiddle Encyclopedia.