Translation:Doctor Wang also has two children.
二 is used for counting and not as a measurement e.g If you are saying your telephone number - 二六零。。。 260... or house nuber, p.o.box But if you are using 2 as a measurement you use 两 e.g 2 books -两本书， 2 apples - 两个苹果 I also noticed you used 俩(lia) instead of 两(liang). 俩 means two but is only used for people, e.g 他们俩(ta men lia) means both of them or the two of them.
You really can only tell if there's a gender distinction in characters if there's a 亻 or 女 radical.
For example: 他/她 - He/she 你/妳 - You/you
But, there are a ton of characters that have different radicals without being related in the slightest. 仔 - young 好 - good 仍 - remain 奶 - milk 傌 - to scold 媽 - mother
In conclusion, Chinese is a bunch of memorization
Doctor wang also has a couple of children. is this wrong? I feel like "couple" in english shares a similar meaning, it too is specifically used for 2 of something. 2 birds - a couple of birds. 2 dollars - a couple dollars. it works with anything in a pair but not as a number on its own, not unlike 两个. am i wrong here?
Doctor Wang is one person so you should have used "has" instead of have