1To grow or sprout (plants, hair, mold, etc.); to appear naturally (usually intransitive).
春になって庭に草が生え始めた。
In spring, grass started to grow in the garden.
最近、顎にひげが生えてきた。
Lately I've started getting beard/hair on my chin.
梅雨で壁にカビが生えてしまった。
Because of the rainy season, mold grew on the wall.
2To cut (teeth); for teeth (especially baby teeth) to emerge through the gums.
赤ちゃんの前歯が生えてきた。
The baby's front teeth have started to come in.
子どもの乳歯は生え始める時期が個人差がある。
Children's baby teeth begin to come in at different times for each child.