Questions regarding DNA for Brittish citizinship applications

I am a bit confused regarding the requirements for DNA for Brittish citizinship through unmarried fathers.

I read that for children born before 2015 (I myself was born in 1989), the father being listed on the birth certificate is proof of paternity but for people born after 2015 DNA is required to prove paternity along with the birth certificate?

I thought Home Office could not require DNA and it should be voluntary to submit it. So why would children born after 2015 need to submit it? Would they only need to submit it if paternity is in question or does every applicant need to submit it.

I’d have thought that they’d make it so applicants born before/after 2015 would have to follow the same rules and that’s why I’m confused.

Will Home Office ask for DNA if my applications approoved if the law changes for people born before 2015?

My sister was born after 2015, will she need to submit DNA from herself and my father for her application?

I’ve seen other topics in which people are confused about this so I thought creating this topic might clarrify a few things if anyone is able to answer the questions.

She does not register as British using form UKF if born after 2015. Ukf only applies to those born before 2006.

Again you are confusing so many different things. I have locked this topic as your requirements are different to hers as a 4 year old and to avoid this topic becoming another repeat of your other existing topic.