Yeah, serotonin transporter gene has a significant effect on personality and response to lifestyle things like medication response, diet, and exercise. Interesting studies on upbringing and trauma as well.
You can test these genes out by doing a 23andme test and uploading the raw data file to a site called promethease. You can the cheaper 23andme test for $99 and upload to promethease for $5 USD. They have sales all the time on 23andme for holidays.
Promethease is linked to SNPedia, a wiki type website with database of different genes, really cool site. Genes that affect muscle fiber type (fast/slow twitch)speed/power, alzheimers risk, cancer risk, personality types (empathy/neurotic/etc). Some genes have transient data, others have a powerful effect with tons of data to back it up.
Exactly, there's a ton of genes affect transporters, enzymes and receptors that affect out personalities and responses to medications, stressors, etc.
A few examples for the ones you mentioned:
Estrogen: BRCA gene linked to very high risk of breast cancer, possibly prostate as well. It affects tumor formation and dna stability, among other things. Doesn't directly affect or is involved with estrogen.
Testosterone: Linked to the number of CAG repeats in the AR (androgen receptor). Lower CAG repeats ; Stronger effect and response from androgens. Too many repeats ; resistance to androgens including complete resistance at a certain number. This is part of the reason why some guys are just effiminate and others are more masculine, including fetal androgen exposure in the womb which shapes the brain and even the penis.
Oxytocin receptor: This is a really interesting and important one. People who are homozygous for either variant have a lot more empathy or lack thereof. This gene controls how sensitive the oxytocin receptor is to oxytocin.
https://www.snpedia.com/index.php/Rs53576
https://selfhacked.com/blog/oxytocin-genes-snps/
Warrior/Worrier gene: This is the COMT enzyme that breaks down adrenaline/dopamine. People with the "warrior" variant are more stoic, resistant to pain and stress. Worriers have higher levels of adrenaline, so they are more fearful/neurotic and sensitive to pain, but they have better baseline cognition thanks to higher dopamine levels. When shit hits the fan, "Warrior" variant has better cognition than "worrier" (under stress). Both are double edged swords. You can also have a hybrid copy and have one of each for mixed effects.
https://selfhacked.com/blog/worrier-warrior-explaining-rs4680comt-v158m-gene/
This is just the tip of the iceberg, you can see how different combinations of these genes can affect personality types, response to drugs/training, stress, etc. There are many more where that came from..
If anyone wants to try it, just get the $99 23andme kit (ancestry only). You just spit in it and mail it back out with the included return box. Once your DNA is processed, you can download the RAW data file and upload it to promethease.com for $5 dollars which will run your DNA data through the SNPedia database and give you all this information and much more.