Different scientists have different views on euthanasia. By euthanasia, I'm assuming you mean: euthanasia of people, as opposed to euthanasia of animals. In either case, different scientists have different views. Euthanasia is really not a scientific issue, because it is not an issue where one can do experiments to reach an answer about whether euthanasia is good or bad.

I googled 'euthanasia' and the 2 main scientific organizations in the U.S. - the National Academies and AAAS, the American Association for the Advancement of Science. In both cases, all the Google citations for euthanasia referred to the euthanasia of animals. Usually, the concern was about making euthanasia of research animals as humane as possible. In one AAAS publication, the question was about whether there was an alternative to euthanasia for all the stray dogs and cats in the U.S. and other countries, especially developing countries, which have many fewer resources than the U.S. for rescuing stray pets. This publication discussed the possibility of something like an injection, which would be simpler than spaying and neutering all the stray pets.

It is something to be avoided at all costs! Insofar as possible. Well that is my view, Others may differ.

Science is a method of learning about the universe. Science cannot measure right or wrong, and thus science cannot tell us anything about right or wrong on the subject of something like euthanasia.

Now, scientists are people, and as people individual scientists have their own beliefs and opinions of what the right and wrong thing to do are, but because science itself has nothing to say on the matter, individual scientists can and do differ in their opinions of euthanasia, just as non-scientists do.