German Law/Paternal rights and obligations
I am a non-EU citizen currently residing in Denmark who has almost certainly fathered a foetus that a German citizen and resident is some weeks pregnant with. She took a morning-after pill of suspect quality that didn’t work and is hesitant about undergoing an abortion. I do not want the baby but she is likely to go ahead with it and is willing to assume full responsibility. I understand that under German law I will be legally liable for 18-25 years of child support according to the Dusseldorfer table and have certain paternal rights, regardless of whether I am in favour of the child being born or not, if the birth does indeed happen. Do I have any options at all in this matter? What are the implications of her specifying the father’s identity or not on the birth certificate? If we decide on the amicable terms we’re currently on that my identity is kept anonymous, are there any implications for the extent of child support she’ll receive? If she changes her mind at a later date and claims I’m the father, is it advisable to take a paternity test and assume paternal responsibility? Is there a difference between whether I do this voluntarily or pursuant to a court order? Does it also have retroactive effect in terms of obligations? Are there any cross-border EU laws that have relevance in this case? Are there any further questions I have neglected to ask that might have interesting answers for my situation? If so, please answer them too!
I like it that you provide "Happy" as your name despite the circumstances. That shows a positive outlook on life. :-)
Because I only have limited time to put into answering questions for free, I'll just answer the most urgent ones, also because we don't want to speculate about all the possible ways this will turn out in the future. If something changes or something dramatic happens, you can always ask me then (and the laws might have changed by then anyway).
1. Child support
If the child lives in Germany, then German child support laws apply. As you have already discovered, the Düsseldorfer Tabelle child support chart would usually apply. The age range however is not enshrined in law. The duration of child support depends on how long the child doesn't have sufficient income of his/her own. That can mean that you will be released much earlier than his/her 18th birthday (e.g. if they take up a trade at 16 or 17 or if they embark on a successful career as a musician or a football player) and it may well extend beyond the 25th birthday (e.g. if they decide to study philosophy and do a PhD). But because these is one the factors that nobody can foresee, let's cross this bridge when we get there.
The amount of child support depends on your financial situation.
You cannot compel the mother to an abortion, obviously. In fact, trying to do so may constitute a crime (§ 240 IV Nr. 2 StGB) if you apply threats. Legally, it's not like her decision is more important than yours, but if the two of you can't reach an agreement, nature just takes its course.
3. Revealing father's identity
If the mother fails to provide the father's identity, she may not receive any or less government funds. Also, she can of course at any time reverse that decision, so I would never count on it. A birth certificate can always be amended later if new information pops up. Even if you compensate her for her silence, she can break her silence. A vow of silence cannot be enforced (legally). Basically, unless you quickly disappear, you will never be completely safe.
If she ever changes her mind, I would always advise you to perform a private DNA test, first to be sure, and second to remove any possibility for doubts that will haunt you otherwise many decades later. These private tests are not expensive.
If the result is positive, you may as well acknowledge paternity, for otherwise you'll get sued and it will just become more expensive. An exception to this might apply if you will live in a country without any judicial cooperation on these matters, but Denmark is obviously not one of those.
4. Retroactive effects
The legal effects of paternity are retroactive in some matters (like inheritance, citizenship law) and not fully retroactive in others. Especially when it comes to child support, you cannot be expected to pay arrears for 5 years if the mother never claimed anything in the meantime. Nobody would expect you to put aside savings every month for something that you never knew will hit you. Usually, the financial effects (in particular child support obligations) will be retroactive to the point in which you first learnt that the mother will pursue these claims, e.g. once you get a letter from a lawyer, the government (if they make welfare payments they will then pursue you for child support) or a demanding e-mail from her.
Overall, my advice would depend on your financial situation and your plans for staying in Denmark or not and what your alternative would be. I have also seen it happen that the emotional situation changes completely once the baby actually shows up.