Here are the implicit assumptions - based on your own cultural bias - and are not facts by any means, just a product of your own biases:
- That it’s solely the mothers job to be focused on her children, and not the fathers.
- That Fathers are not capable of caring for children, or providing equivalent nurture and care as a woman.
- That care from a family group is solely mother and father, that social groups, grandparents and other family members - or associated surrogates are incapable of providing sufficient care.
- That mother’s have a moral obligation to dedicate themselves full time to their children, but not fathers.
- That the burden of choice between childcare and career is only something that falls on the mother.
None of these are facts, just products of your own social and cultural biases. If any one of them were considered differently - you’re nonsense argument falls apart.