Children of brother and sister (yes!) creates duplicate records.

Question

How do I add children (x9) whose parents are brother and sister, without getting duplicate records? This was in the early 1600s, not recently!

Answer 1

You can make the brother and sister partners and then add their children as "normal". From the FAQ:

Q: How do I create a marriage between two related people?

Select the first person in the partnership. Then click 'Add partner/ex' followed by 'Partner with existing person on tree'. Choose the second partner from the list then click the appropriate button.