Beneficiaries within the 1st degree of consanguinity

We have always favoured defining the beneficiaries of a trust as the client, spouse and relations within the first degree of consanguinity and the descendents of any beneficiary. This has the advantage of being both dynamic (if more children are born) and avoiding having to provide details of all the beneficiaries and their guardians if minors.

However, we are finding that many people don't understand consanguinity, so we decided to change our trust template to replace it with the spouse, parents, siblings and children of ....

While doing this, Helen,? being her usual thorough self, Googled the definition of 1st degree of consanguinity, and found that it is defined as parents and children, and that siblings are 2nd degree of consanguinity.

Our first concern was that siblings were not, therefore, included as beneficiaries of most of the trusts that we have drafted. However, on reflection, as they are descendants of other beneficiaries (the parents), they are in fact included, so no problem there.

The next issue is that I studied consanguinity at University when working towards becoming a CA(SA) and I'm sure that siblings were included in the first degree, so then I Googled the same question. I found conflicting statements.

For example, I quote from the National Human Genome Research Institute:

"A first-degree relative is a family member who shares about half of their genetic information with specific other individuals in their family. First-degree relatives include an individual’s parents, siblings and offspring."

Now, by my reckoning, siblings share about all their genetic information, so that would make them closer relations than parents.

SARS, on the other hand produced a diagram showing the siblings as 2nd degree relatives.

So, best stick to simple wording that everybody understands.