system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do I look NOTHING like my family?

I know that genes play a huge part on how much you look like your parents but I don't. I'm hispanic with straight light brown hair and green eyes and my family looks are along the line of dark brown/black wavy-curly hair with brown eyes. I know only one family member that has light eyes which was my dad's aunt, but other than that, nobody else. I'm also tall compared to my family 6'2-6'3ish and my family is about anything ranging from 5'0 to 5'9. Can anyone explain this to me, I've searched everywhere but I still haven't found an explanation to this.

Just so you know in advance I'm not adopted, I spent nearly $100 for a DNA test and I'm a math for both dad and mom.
gpt
The short answer is that genetics is complicated.

We'll keep it to a simple version to start with, and only discuss genes as having two possible types: *recessive* or *dominant*. You get one copy of each gene from your mother, and one from your father. For a recessive gene to be expressed (ie, blue eyes), both copies have to be the recessive gene. That is to say, if even one is the dominant gene, then it will dominate, and you will have the trait it codes for. Generally, a dominant gene is shown by a capital letter, eg "E", and a recessive gene with a lower case, eg. "e". Two copies of the dominant is written as EE, two copies of the recessive as ee, and one of each as Ee. These are called *genotypes*. The physical representation of a genotype is called a *phenotype*. Both EE and Ee have the same phenotype (external appearance). Someone with a dominant phenotype may be either EE or Ee. A recessive phenotype **has to be** ee.

Taking the example you used, brown eyes is coded for by a dominant gene in humans. If we call this "B", and the recessive green-eye gene "b", then we know you have the genotype "bb". You mentioned one of your relatives has light eyes, this tells us that there are likely to be some copies of the "b" gene floating around your family. For you to have two copes of "b", you must have gotten one from each of your parents, thus their genotype is Bb. This is how you've gotten green eyes even though your parents don't; they each have one version of the green-eye gene, it is just hidden. You mentioned that your family is hispanic, the most common gene variant in that particular population group is "B", so the chances of two people with Bb meeting is relatively small, hence why your extended family don't have many green eyes. As for your siblings (if you have any), the chance of a child getting two copies of "b" from heterozygous (one of each) parents is 1/4. 

Now, that's a simple case of genetic inheritance, known as *Mendelian inheritance*.* Height is a bit more complicated. Rather than a single gene making you either "tall" or "short", there are at least 15 different genes, each of which will add or take a few centimetres. The combination of genes you got by random chance may have boosted your height.

The other complicating factor is the *nature vs nurture* debate. Namely, for most traits, the actual outcome is a result of a combination of your genes (nature), and your environment (nurture). As a general rule of thumb, nutrition has improved markedly over the last century, and this has contributed greatly to increased height. The average height a few centuries ago was 5ft or less, it's now close to 6ft in a lot of Western countries. The genes in the population haven't changed, people are just eating better and thus able to get the full "potential" out of their gene combination.


*For those who want to know more, eye colour isn't really properly Mendelian. Both blue and green eye colourings are recessive. They're "co-recessive", and if you have both you'll get some combination of green/blue. "Co-dominant" genes (some blood types) also exist, as well as various levels of dominance / partial expression.