I think in the overwhelming majority of cases I can think of that truth IS love when it comes to trying not to emotionally mess up your children. That goes for issues separate to parentage as well.
We don’t have closed (anonymised) adoption any more - and the names of the biological parents of adoptees are stated on their birth certificate which is intended to give the adopted person a way to know their birth family’s names and the BC also holds the full name that the child was registered with at birth.
With donor conception, we don’t explicitly record genetic info if children on birth certificates. Which I think is right and often protects children’s interests.
The UK removed anonymous sperm/egg or embryo donation. The child has a legal right to request their donor’s name and address at 18. They can request to know if they are donor conceived (from treatment in the UK) at age 16. UK charities like Donor conception Network offer info and resources to tell children in an age-appropriate way about their genetic origins.
This quote below is from someone whose legal case contributed to changing the law that removed donor anonymity in the UK- she is against donation per se as is the case for some donor conceived people who are given no legal opportunity to find their donor.. the objection seems to be substantially rooted in the reaction to the lying and the adverse effects that has on identity for the child:
‘Despite my sense of injustice, I love and am loyal to my family. But it is still a very sensitive and prickly issue, and relationships can feel deeply strained at times. My mum and dad - who are now divorced - have made massive efforts to understand how I feel, but it can still be very difficult. I think that like many people who go through donor insemination, they were naive and deeply focused on themselves and their infertility.’ She continues:
One of the most upsetting things for me about the way I was brought into the world is the blatant double standard involved. My mother's need to have a genetic link to her child was valued, while my need to know, love and understand the father with whom I have a genetic link was not.
www.theguardian.com/lifeandstyle/2008/nov/14/family-genetics
I think there are obvious parallels.
Live how you want, but you shouldn’t have the right to force your own identity preference on to others including your kids via the medium of their legal identity documents.