It's a reality that in taking care of animals that often you need to know what sex they are.  Fortunately you can very easily tell what sex a kid is immediately after they are born. 

There is often more than one way to do things and we can get stuck thinking it should be done one way when the other way is so much simpler.  The thing is do not think that you must look for a penis or testicles to tell the boys from the girls.  With new kids you might mistake the umbilical cord for the penis and the testicles may be hard to find.  Also all boy goats do have teats just like the girls at that age.

It is much easier to look under the tail to tell the girls from the boys.  This can be done the moment the kid is born with no mistake.

• Lift up the tail and look. 
• Both goats will have an anus directly under the tail.
• Boys will have only one hole under the tail.
• Girls will have a vagina directly under the anus.
• Girls will have two holes under the tail.