The Ukraine was reported to have put in conscription registers for women months ago. I read women who are 18-60 and 'fit for military service' in many professions were required to register at the end of last year though how many have been called up so far is in question . Reservists usually get called before conscripts. Russia is widely reported to be using conscripts in Ukraine.
My family haven't been discussing it about Ukraine. We have discussed it in regards to the US, because I'm American and the Selective Service System being challenged again has been a story I've followed. We've used that and my own naturalization process to discuss the responsibilities, benefits, and risks of citizenship and residency & government powers.
We discuss that it's generally been considered and in some countries legally stated that part of a man's citizenship responsibility has been to protect. The Selective Service System's 'motto' is bluntly 'It's Your Country. Protect It', and non-citizen resident men are included in that. It's only recently been applied to women in a few countries in pretty much the same for both sexes, but women have been brought into conscriptions on limited basis in conflicts in our history and some choose to go into war fronts.
I don’t know if it’s possible to refuse to kill others and serve in another way but I am going to sugar coat things and tell them it is.
Conscientious objectors played many important roles in WW2, so I'd be surprised and frustrated if the 15 year old hasn't covered them at all in learning about it.
In our family, we have a mix of military and conscientious objectors and we've also discussed that.
I have decided just to focus on the fact that in the past our country also used to view women as not suitable to be in the armed forces but now they are more enlightened and do serve on the front line. Ukraine will perhaps change its position over time.
Nothing about conscription is enlightened, conscripting more people is not enlightened. It's a desperate move of force by powers that cannot get enough volunteers that it must use the threat of imprisonment, fines, and violence to get people to fight and kill for them in the way they want.
It's been discussed in some spaces that part of the reason is the issue Ukraine, like many countries, has had issues with non-military forces - some they've brought into the fold, but the militaries are not the only ones fighting and that can cause issues.