This Reddit post attempts to explain it:
From what I understood, Helle Anker used Freddie Holst's sperm to have
a kid (Martin Anker) but destroyed all evidence at the clinic she had
set up. She then she must've told Martin to look up the code at the
clinic to find his real Dad and when he did he would've seen he had a
brother (Emil) and that must've been how they met and I guess how Emil
found out about his real parents.
So his 'creators' were his Dad and the woman responsible for setting
up the clinic.
This Guardian commenter has a similar explanation:
For anyone wondering about the whole Emil/Morten relationship and why
Helle Anker was referred to as Emil's "creator", I believe it stems
from the fact that Helle Anker set up the fertility clinic. She used
Freddie Holst's sperm for herself so that she could give birth to
Morten, and later in life gave Morten some more information about his
beginnings. As Helle ran the fertility clinic, she was able to give
Morten the infamous code for Freddie Holst's sperm donation to
Anne-Marie Larsson. This enabled Morten to find his half brother, Emil
Larsson. This backfired spectacularly. Emil resents the fact he was
ever born and takes revenge on Freddie (his sperm donor father) and
Helle Anker ("his creator" i.e. The lady who ran the fertility clinic
in which Emil was artificially inseminated). Emil was none the wiser
about his beginnings until Morten contacted him.