Noun, する verb, and の adjective
せいしょく
今、生殖器が二つある女の子と付き合ってるんだよ。
I’m dating a girl who has two reproductive organs.
Life, when it multiplies (multiply), is doing reproduction.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.