Clanfolk need to have a private room with a Double Sleep Mat or Double Bed, they also need a very high mood.
Tips:
Their moods must both be over 7500 when the wife enters or leaves the bed.
The wife cant be hungry.
If they already have a baby it needs over half way grown into a juvenile.

Giving the couple "time off" can help improve the mood.

Private room is simply when Clanfolk are the only ones sleeping in a room. Of course married Folk still get the private room buff sharing the room with their partner.

In cold weather if they are using sack clothing/furs they will have a worse mood. try to make wool clothing for them.

Linen clothes boost mood so summer is an easier time to get high mood.

The left mood number is the one you want over 7500.
Private room.
Once they are pregnant a new bar will appear.

To gain new clan member you must have an adult without a partner.

A worker with these 2 requirements met: "Maxed satisfaction" and "Potential Partner"


If the requirements are met you will get this popup.

If you add them by clicking the house icon with the arrow pointed in the above image. They will join the family.