The most important one, The one with the worse symptoms.
Answer:
From fertilization and to the end of the second week.
Explanation:
The development of the fetus is divided into three periods, established by most embryologists: pre-embyonic period, which goes from fertilization to the second week of development, embryonic period, which goes from the third week to the eighth week, and the fetal period, which goes from from the third month until the end of pregnancy.
The pre-embyonic stage begins at fertilization and remains until gastrulation. By the end of the second week the embryo already has the neural tube formed, although it is still open at both ends.
Can you be more detailed with the question?
Answer: this question is opinionated so I'm just winging it for you-
I would not mind because I don't really want to have kids. If they were upset about it and it was affecting their mental health, I would then in that case feel empathy towards their pain and support them the best I could.
