of different age as the tow physicians are,they are of the s

首先,原句为让步状语从句的倒装,还原为：
Although the two physicians are of different age,they are of the same interest.
其次,be of different age 与 be at different age相当,可以替换.
不过,be of the same interest 中的“be of sth”指的是“拥有,具有（某种特性）”,故此处不能用in代替.