Detailed explanation: Mother-in-law is old and weak, unable to force, unable to get legal protection.

In fact, my mother-in-law's feudal thoughts are serious, and she wants to carry on the family line, insisting on her own opinions and refusing to give up. This is a far cry from the word "compulsory".

Conclusion: It is not illegal for a mother-in-law to insist on giving birth to her daughter-in-law.

Note: If a woman clearly states that she will never give birth before marriage, then she has the right to refuse to give birth. If she has never made any statement before marriage, then as a wife, she is obliged to give birth to her husband's children according to family planning (except for health reasons). But the mother-in-law has no legal relationship.