Tessa's Kids: My Nieces and Nephew

My sister Tessa (pictured with her son top) is 6 years younger than I am.  She has three kids.  Marissa is the oldest (17), Cody is the second oldest (16) and Tearra is the youngest at 10.  There's a funny thing about the family and kids: we tend to have kids in clusters.  Tessa had Marissa within weeks of our other sister Tina having Alloura (her eldest).  Tessa, Ted, Lena (Lyuda's sister) and Lyumdila/I all had kids within a few months of each other (Tearra, Theo, Vsevolod and Avrora, all born within 6 months of each other).  Ted and I repeated that again with Orest and Chris.  This also happened in the past with our aunts and our mom.  Cody, the other cousin (Tina's other daughter, Mikaela) and Sasha (Lena's newest son) are the outliers.  Cody is 16, Mikaela is 15 and Sasha (Alexandr) is 3.