What Is A Half Sibling (and How It Differs from Step Sibling)

We all know that family can mean everything. Family can be who we go to celebrate or commiserate. Perhaps you see family every day or maybe once a year but either way the chances are that the bond has remained unbreakable over years gone by.

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In today’s society family has become a lot more varied with divorce, remarriage and adoption on the rise.

The family has stopped simply being a mum, a dad and their 2 biological children. Instead family is now a much more complex term. One relation that is on the rise is the half sibling.

So, What Is A Half Sibling?

What Is A Half Sibling

A half sibling is someone who shares one biological parent with another person. For instance if you share a biological mum but have different biological dads that will make you half siblings.

The term half sibling is actually an umbrella term covering both maternal half siblings meaning that two people share a mother and paternal half sibling meaning that two people share a father. Half siblings often occur when one parent enters into a new relationship and has more children.

What Is The Difference Between Half Siblings And Step Siblings?

Step siblings are purely related through marriage. So, if two people already have children from previous relationships then marry each other then their children become step siblings.

This means that whereas half siblings share one biological parent whereas step siblings share none. In terms of genetics there is a big difference between step siblings and half siblings as step siblings share no DNA whereas half siblings share 18-33%.

Is A Half Sibling Still Considered To Be A Sibling?

The simple answer to this question is, yes. Genetically speaking they are still considered to be siblings because they share genetics which were inherited by a parent.

Legally speaking the answer is usually still the same as half siblings usually share one legal parent.

Interestingly, it has been found that some half siblings have a stronger relationship than some full siblings especially if they grew up in the same house as one another.

Are Half Siblings Still Considered To Be Immediate Family Or Are They Wider Family?

Half siblings are generally considered to be immediate family. This is because the immediate family includes any parents and any siblings regardless of genetics.

This means that in court a half-sibling would be classified as immediate family. Similarly, if anything were to happen to a half sibling and a work place only offered compassionate leave for immediate family this would still be covered.

Half Siblings are considered to be more closely related than cousins because they still share one biological parent whereas cousins only share biological grandparents.

Obviously, parents are a much closer genetic link than grandparents are so the DNA shared by half siblings is likely to be stronger than that shared by cousins.

Do Half Siblings Usually Share A Surname?

What Is A Half Sibling

This question is impossible to answer as it completely depends on personal circumstances. If a mother and father are married and the mother takes the father’s surname then the child will probably also inherit the father’s surname.

If that father goes on to remarry and have further children then the same situation will probably occur meaning that both half siblings share a surname.

However, if parents weren’t married or the mother chose to keep her maiden name then this could be different. Similarly if they are maternal half siblings from different marriages then there is a good chance that they will have different surnames.

Final Thoughts

Although half siblings and step siblings are often mixed up we hope that this will have helped to clear up the differences between the two. It is important to remember that both legally and genetically speaking half siblings are still siblings.

Exactly how half siblings come to be can vary drastically and some will share a mother whereas others will share a father.

It is also important to remember that different sets of half siblings will vary drastically for instance, some might share a surname whereas others might not, some will have the same color whereas others might not and some may be the same race while others may be different races to one another.

The most important thing to remember is that families come in all shapes and sizes but as long as the love is there then that is all that matters.


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