Final answer:
The surgery date and the twins' age at the time of surgery are not provided in the information given.
Step-by-step explanation:
The surgery on the twins was not specifically mentioned in the provided information. However, the twins were put up for adoption in 1968, so the surgery would have taken place after their adoption. The exact day and date of the surgery are not given. As for their age, the twins were born in 1968 and the surgery was performed after their adoption. To determine their age at the time of the surgery, we would need more specific information regarding when they were adopted and when the surgery took place.
The information provided does not specify the exact day or date on which the twins' surgery was performed. Additionally, the ages of the twins at the time of their surgeries are not mentioned in the references provided. To find out on what day or date the twins were operated on and how old they were at the time of the surgery, further information or context would be needed. Conditions like the twins' can indeed be of significant interest to medical researchers, and it is common for scientists to monitor such rare cases throughout the individuals' lives to gather valuable data.