Not a biologist, but my understanding is that, due to various reasons, life forms need to be carbon or silicon based.
Agreed that the claims of spores on Mars are likely bogus.
For sure, carbon is by far the most versatile element in the periodic table and the only one capable of forming organic polymers.
What I wonder is whether deoxyribonucleic acid, aka DNA is the only molecule capable of carrying information for the development and reproduction of life. If non-DNA based life exists, I wonder if we would even recognize it.