Steins;Gate - episode 8 - 24 May, 2011

Okabe explains the nature of the world line shift to Daru and Kurisu and that he is the only one who can remember changes to the timeline. Okabe decides to resume his experiments by having Kurisu send the next D-Mail, however Moeka requests to send one instead. When the mail is sent, Okabe shifts to a new timeline where no one else remembers Moeka. The next day, Ruka comes to the lab, asking to send a D-Mail so that he would be born as a girl. Using an urban myth about how a diet can affect a baby's gender before birth, the group send a D-Mail to Ruka's mother's pager, sending Okabe to another world line, though he does not notice anything particularly different about Ruka and wonders what has changed. (Source: Wikipedia)