Fertility clinics in Ukraine began offering what's known as cryo preservation of sperm and eggs to servicemen and women in 2022 at the start of Russia's full-scale invasion.
https://www.bbc.co.uk/news/articles/cqxd9549y4xo
all soldiers' samples are preserved for free for up to 3 years after their death and are available for a partner to use with prior written consent.