According to the Wikipedia article Phenotype:
“An organism’s phenotype results from two basic factors: the expression of an organism’s genetic code, or its genotype, and the influence of environmental factors, which may interact, further affecting phenotype.”
So, that does not take into account one’s sansaric gathi at all.
In Buddha Dhamma those sansaric gathi actually DETERMINE one’s birth. Once that first step is complete then of course one’s parents (genetics) and the environment that one grows up, will play roles.
But one’s parents are also determined by one’s sansaric gathi, so that plays the key role.
Of course, one’s gathi (or gati) could change significantly if one’s environment (especially friends and associates) changes drastically. So, that is also an important factor.
Above two key factors are discussed in the following posts and in the links therein:
Buddhist Explanations of Conception, Abortion, and Contraception AND
The Law of Attraction, Habits, Character (Gati), and Cravings (Asavas)