True allergies to cow's milk are relatively uncommon. Only 2 to 3 percent of children are allergic to milk, according to the AAP, and almost all of them outgrow it by age 3. (Learn the difference between a milk allergy and lactose intolerance .).
The underscore [ _ ] (also called underline, underbar, low line, or low dash) is a character that originally appeared on the typewriter and was primarily used to underline words.
Intra_word_emphasis are disabled, so the underscores in that first part should show up normally. There's a long-standing bug that the preview doesn't handle this correctly, but it should show up normally in the post.