https://www.yahoo.com/movies/m/50c4ac7a-a95b-3e0e-90a7-0972d3cd9c20/will-supergirl-ever-introduce.html

Supergirl went through some major cast changes when it moved to The CW, and one change that has proved pretty intriguing was the introduction of Lena Luthor. The lesser-known Luthor of DC Comics fame has become a somewhat ambiguous ally to Kara. The

It would be cool!

It could happen as Lex Luthor appearing as a child.

Who Could Play Lex Luthor On Supergirl? (http://screenrant.com/who-could-play-lex-luthor-on-supergirl/)

Great choices