It can be difficult to accept when things don’t turn out the way we planned. The fact that your child is trans / non-binary does not necessarily mean you won’t still be a grandparent…anymore than the fact that a cisgender child may choose that they don’t want to have children, or may not be able to have children.
Trans / non-binary parenting options
Trans women and non-binary people assigned male at birth, may choose to have sperm frozen prior to any hormone and / or surgery treatment, to give them parenting options in the future.
Likewise, trans men and non-binary people assigned female at birth, may choose to have their eggs frozen prior to any hormone and / or surgery treatment, to give them parenting options in the future.
Trans men and non-binary people assigned female at birth may also choose to put their hormone treatment on hold to allow their body’s female hormones to start functioning again in order to become pregnant. Assuming the individual still has their female reproductive organs (i.e. they have not undergone a hysterectomy) this is viable. There are emotional factors to consider in that a trans man / non-binary person would be dealing with the psychological impact of carrying a child, which is widely recognised as a ‘female’ role.
There are also the same options available as would be offered to any individual with fertility issues. Trans / non-binary individuals may choose to foster or adopt, or consider surrogacy options.