Given the pregnancy tag, I'm adding this to "How is that even possible" for obvious reasons.

Given Hakase I am not surprised anymore

Gaketsu said:

「ふふっ♪……相生さん、男の子がいいですか？女の子がいいですか？」

「ちょ、なのちゃーん!?　……はかせー！ドユコトー!?」
「だって、好きな人同士がお布団でイチャイチャしたら子供ができるって言ってたんだけど」
「誰が!?」
「阪本。」
「Σ(0д0;) また俺かよ!?」

――――――――――――――――――――――――――
「日常のAfter Years」とは、また別の時間軸。
お出かけ前のタイムトライアル、12分延着。

コメントいただいたので取り急ぎ補足。
はかせはお子様なので、お布団でイチャイチャするだけで男女関係なく子供ができると思っていたようです。

"Tee-hee♪... Aioi-san, do you want a boy? Or a girl?"

"Wai..., Nano-chan!? ......Professor! What's this about!?"
"But, I was told that people who like each other will have a kid if they flirt in the futon."
"Who said that!?"
"Sakamoto."
"Σ(0д0;) Why me again!?"

――――――――――――――――――――――――――
An alternate timeline to the Nichijou After Years.
There is a 12-minute delay of arrival before exploring the time trial.[Translator's note: ...What?]

I will quickly correct any comments.
Because Professor is a child, she would think that either men or women could have a child just from flirting in a futon.

Xarams said:
There is a 12-minute delay of arrival before exploring the time trial.[Translator's note: ...What?]

I'm not real clear on this myself, but it's literally something like "A time trial before going out, 12 minutes late."
Something like he did this drawing as a speed run before leaving somewhere, and ended up leaving 12 minutes late because of it?

Xarams said:
I will quickly correct any comments.

That should be "An addendum due to comments I received."

And this image actually makes total sense. The Professor has equipped Nano with some kind of baby making feature that gets activated when she experiences certain emotions towards another person. Sexual activity and gender would be irrelevant.

Well, aside from the sign on yuuko's head, it can just as easily be interpreted as nano being happy about her weight-gain feature.

Wow, so Nano's a Third (from Armitage).