I'm not sure which specific 'he's my baby girl stories' you're referring to. It could be some personal and unique tales within a family or a group of friends. Maybe it's about a special bond between two people where one refers to the other as 'my baby girl' in an endearing way, like a father - daughter - like relationship even if it's not a traditional one.
One common theme is caretaking. Just like taking care of a baby girl, the wife takes on the role of nurturing the hubby, like making sure he eats well, sleeps enough, etc. Another theme could be emotional support. When the wife treats the hubby as her 'baby girl', she's often providing a safe space for him to be vulnerable and express his feelings.
Well, one story could be that the hubby got sick and had to be taken care of like a baby girl. His wife cooked his favorite soups, tucked him in bed, and read him stories just like one would do for a little girl. It was a time when their roles reversed a bit and it brought them closer.
There was a time-travel adventure where a girl goes back in time and due to some time rift magic, she is turned into a baby girl in the past. In this state, she is adopted by a kind family. As she grows up again in this new form, she starts to remember fragments of her real identity and has to find a way to get back to her own time and her original form.
This is an unacceptable and dangerous practice. The risks are numerous. It can cause infections as semen may carry various bacteria and viruses. It can also lead to digestive problems in the baby as their system is not equipped to handle such substances.
This is a very serious and wrong idea. Babies, whether boys or girls, have very delicate digestive systems. Their diet should be carefully selected. Foods for babies are strictly regulated to ensure their growth and development. Any abnormal or inappropriate substances like semen should never be given to them as it can lead to severe health problems and is also unethical.