Acacia and Froese were together for a decade at least, maybe even more. They seemed content with their adopted family and never had children of their own during that time. In fact, it's hard to tell if they were anything beyond a partnership between a Bishokuya and a chef.

So what happened exactly to cause them (or one of them) to decide that it was a good idea to conceive some children WHILE they were out in the incredibly dangerous Gourmet World? With the information present from the plot so far, the only possible time frame when conception could have happened was after they left with the nitros and before they encountered GOD (and later returned). Or was the whole children thing an accident?

I guess the moral of the story is...use protection? Otherwise your offspring might come and fuck up your plans 500 years later.