I like LnB's suggestion of "no kids sorry but babes in arms welcome"!

As for being for a first baby only - I had one for my first only but I think any baby is deserving of a celebration and if people choose to have one for a subsequent child, then why not, pretty sure there aren't rules around it being only for a first child? I know a lot of people who have had more of a blessing way for their 2nd child so it's more about getting together, painting a belly cast etc. than gifts. JMO though! My gf had a gorgeous blessing for her recent 3rd child, people were asked to donate a piece of fabric that was 30 x 30 cms so she could make a birthing bunting as she was home birthing (after a c/s and vbac in hospy!) and I thought that was a lovely idea and I was spewing I couldn't go!