Note from The Future: please mentally replace all mentions of “gender” with “sex”.

Doc: With a sample of Heinkel’s blood and my brilliant accelerated growth method…I will solve the mystery of his/her gender once and for all!

Ta-da!

…

Rip: Hey, Doc, my alarm clock is–

[BOOM]

Major? Doc just blew up the lab. Yes, again.

Doc: Mine eyes have seen the glory…

Major: But why didn’t you look at the chromosomes?

Doc: If I did things the easy way, I wouldn’t be a mad scientist!