I am unmarried was in a dead relationship with a man - living in a house with him in separate bedrooms, except for one day in months we were intimate and I conceived my son, and never again after that - finding out at 41 after years of prayer that I was pregnant, and was never intimate with the father again even while living under the same roof - the relationship did not work even as a friendship again as the father is a liar and manipulator and takes up no responsibilities. I had my son under huge stress living with the father, losing my job because I was pregnant. Having to go through a CCMA trial and winning... therefore Forced to live under the same roof as the father at least until my son was born as he threatened not to pay any medical costs if I did not. SO.. Under duress I was bullied into having the fathers surname and mine registerd at Home Affairs as my son's, but luckily not double barreled so he has his fathers surname and then mine last - would I be able to drop the fathers surname together with the second name to just have him known by one name and one surname? I have now even had to take the father to court to get maintenance out of him!

First this is a legal issue so has been moved to the proper forum. Second, ANY question on law needs to include your general locale as laws vary by area.

A birth certificate is a legal document and cannot be altered without legal action. In the US a person can use any name they want as long as there is no intent to defraud except where a legal name is required.

It may also depend on how the name is listed on the birth certificate. For example someone could be listed like:

First Name: John
Middle Name: Percival Englebert
Surname: Miller Johnson Smythe

In that case, I believe he could use John Smythe as a legal name.

Thank you! Do I have to go to Home affairs to change anything then? Or can I just use his first name and Last "last" name then to register anywhere like school, medical Aid etc?

First please don't use the Comments feature for follow-up, use the Answer options instead.

The school or any other official agency will require that you present his birth certificate for registration. When you register him you request that they use John Smythe as his name. They will tell you what they can do, but, if the name is listed as I suggested, it should be acceptable.

And telling us where you live helps, obviously it is not the US.

As noted by Scott, the name on his birth certificate is his legal name, till it is changed, In the US, that involves going to court for a name change and would require normally the fathers permission.