My two sister-in-laws both have 'may' as a middle name which is the same as their mum... they are also all born in May - presuming thats how the name came about....
I thought it was odd at first as i've never seen all girls/boys have the same middle name - only sort of one child... but i don't see anything wrong with it. I just wasn't used to it.

How about a varient... my mum is Leanne and I am Kirsty-Lea.... so one of my daughters i'm going to change it slightly and have Kaeleigh or Ashleigh. So the sound of 'Lea' is still in there but its unique to her.