Why does my younger brother always want to play with me?

Young children often form an attachment to older siblings. The sibling is familiar, being a member of the family, but smaller than an adult, so seen as more accessible. Many younger siblings hero worship older siblings up until the teenage years.

Sadly this can become tiresome for older siblings, who quickly get bored with younger children. But as I tell my children: "Always be nice to your younger brother. You never know if you'll need a kidney transplant one day."