Hold up I'm confuse... Why did she get the baby in the first place?

She stole Fengfeng's sperm but, the sperm was actually switched with Yiyi before she got it.

Oh I see thank you for explaining ヾ(❀╹◡╹)ﾉ

She stole the embryo thinking it was Feng Jinyao’s because that would make the child the heir to the family business since it would be the first son’s first son, but she doesn’t know that Feng switched his embryo with YiYun’s to have RouRou, so she actually has YiYun’s baby