One strategy that helped streamline the Duggars' lives was a “buddy system” established by mom Michelle.

Their fundamentalist Christian faith holds that women’s highest calling is as wives and mothers running happy households.

The one notable exception: oldest daughter Jana.

Duggar family

At 31,Jana is still unmarried and living at home.

Her other big passion is drinking coffee; the brew figures prominently in herInstagramfeed.

So why is she still single?

Jana Duggar holding coffee cup

Fans have some thoughts on the topic.

Johannah, Jennifer, Jordyn-Grace, and Josie are all tweens and early teens.