My grandma has had 8 children 4 of each gender, all within 1.5 years if each other.
My mum had me, 7 years later a m/c, then 6 mths later fell preg with my sister and a year later my brother.
Both DH and I have even numbers of genders on each side. DH has 4 sets of twins, each generation, non identical. I have 2 sets of twins on my family side, 1 from great grandparents side and 1 from my cousin, both non identical.
It is all very interesting, genetics, that is!