Influence yes, determinism no

Although the genes and the environment are related to the most different traits of human behavior, that does not mean there is a biological or cultural determinism. Only because one trait presents genetic and environment influence, this does not mean that nothing can be done to change it. Behavioral traits are, in general, influenced by multiple genes and environmental factors, and above all, the powerful role of the Spirit has to be considered, since through its free-will it can exercise a remarkable influence over the genes and the environment in which it is inserted.

To attribute human imperfections to the body itself, would be the same as to believe that man is a machine, a toy of matter, with no responsibility over his deeds, and this is an absurd. Kardec reminds us that there is no irresistible entrainment, when there is a will to resist it. (LE, item 845.)

The influence of the genes in human behavior, just like the influence of the environment, is linked to probabilistic trends and not to a predetermined programming. In other words, the complexity of the majority of the behavioral systems shows that the genes are not the destination, nor can we blame our Creation for being like we are. The Spirit is the "Master" of Matter. Genes and environment influence the incarnate Spirit, but he is always the master of its own decisions, such as making choices and choosing his path. Finding a gene that is associated with a disorder does not mean that it is a “bad” gene and that it should be eliminated. For example, a gene associated to the search of new things can be a risk factor for an antisocial behavior, but it may also predispose to scientific creativity. Therefore, the genes that predispose to drugs addiction can also predispose to become a talented artist, an innovative scientist, or a creative entrepreneur. The Spirit can always "choose" the paths to which his genes are going to be oriented.

To grow without a father at home, as statistically proved, correlates with problems such as abandonment of studies, idleness and adolescent pregnancy, but not all young people, which grow up without a father at home go through these same mentioned problems.

The idea that all criminals are bad because they had a difficult life does not apply any longer among the experts and common people. Many psychopaths grew up in homes without major problems and Machiavellian personalities can be found in all social classes. An old joke tells us about two social workers talking about a problematic child. “John comes from a broken home”. “That’s right, John destroys any home”. 

Andre Luiz weaves remarkable views on the topic:

[...] The earthly creature inherits trends rather than qualities. The first surround the man who is reborn, from the early days of struggle, not only in his transitory body, but also in the general environment to which he was called to live in, improving himself; the second results of the individual work of the embodied soul in his own defense, education and improvement within the blessed circles of experience. If the reincarnated Spirit is attracted to low tendencies, he will develop them when he finds them within the new framework of human experience, wasting a precious time and belittling the sublime opportunity to rise. However, if the soul returns to this world and is willing to accomplish his enlightenment, he will maintain himself at a distance from the less noble requirements of body or environment, triumphing over adverse conditions and achieving victories of the highest significance for eternal life. Therefore, in good conscience, nobody can complain of destructive forces or asphyxiating circumstances, when referring to the circle where he was reborn. There will always be, within us, the light of inner freedom showing us the ascension. By practicing the spiritual ascension, we will improve forever. This is the law. (Missionaries of Light, Chapter 13).

And Emmanuel, in turn:

Most diseases, including dipsomania, are contagious. However, this does not imply a biological fatalism that engenders the misfortune of beings, because many Spirits, in tracing the map of their fate, seek by choosing a certain instrument, to extend their possibilities of succeeding over the matter, as a fact resulting from strict and moral laws, which, in the same manner as in the earthly environment, prevail in the spiritual world. (The book "Emmanuel", Chapter XXIV)

In Kardec’s Encoding we find the following statements:

To apologize for one’s misdeeds due to the weakness of the flesh is nothing but a subterfuge to evade responsibility. The flesh is weak, only because the Spirit is weak. This solves the matter and leaves to the Spirit the responsibility of all his actions. (RE, March 1869)

[...] Therefore, be convinced that man does not maintain himself vicious, unless he wants to continue being vicious; and that the one who wants to correct himself, can always do it. Otherwise, there would be no law of progress to man. (ESE, Chapter IX, item 10)

Without the free will, man is not to blame for evil, and has no merit too in doing well; and this is in such a way recognized that in the world there is always blame or praise regarding the intention of action, which means regarding will; well, who says will, says freedom. Man could not, therefore, find excuses in his body for his faults, if he does not abdicate from his own reason and human condition, to resemble animals. If it is like this for evil, this it should be for good. But, when man does good, he has a great care in assigning the merit in his favor, and does not attribute it to his organs, and this is a proof to which he instinctively he does not resign, despite the opinion of some systematic, when referring to the most beautiful privilege of their kind: the freedom to think. (LE, item 872)

If this is applicable to evil, it should also apply to good. But when man does well, he takes great care in consigning merit to his advantage and does not attribute it to his organs. This is a proof to which he instinctively does not resign, despite the opinion of some systematic, the most beautiful privilege of their kind: the freedom to think. (LE, item 872)

Genes and environment should be considered as evidence

Genes and environment should, therefore, be considered as part of the evidence to which the Spirit is linked to in his reincarnation experiences. Genes that predispose to obesity will lead the Spirit to combat food craving. Genes related to drug addiction invite the Spirit to the development of self-control and the exercise of creativity. In the same way, permissive environments, or where there are bandits, are opportunities to fight lower tendencies.
Kardec, answering a reader of the Spiritist Magazine, who inquired as to the origin of his violence, writes:

For me it is clear that your Spirit is naturally irascible; but as each one carries its original sin, that is, a remnant of the old inclinations, it is not less evident that in your previous live, you were a man of extreme violence, and that you paid a high cost for it, perhaps with your own life. 

In the spiritual world, your other good qualities helped you to understand your mistakes; you decided to overcome yourself and, for this, to fight in a new life. But, if you had chosen a weak and lymphatic body, your Spirit, finding no difficulty in this fight, would have gained nothing, and this would mean that you would have to start over. This is why you chose a bilious body, in order to have the merits of the fight. (RE, July 1863)

And Kardec goes on:

The Spirit, disconnected from the matter, in the wandering state, choses his future lives, according to the level of perfection he has reached. As we have said, his free will consists in this. This freedom is not canceled by incarnation. If he gives in to the influence of matter, then he is defeated in the trials he himself chose. (LE, item 872)

And finally:

To prove that man is responsible for all his deeds, is to prove his freedom of action, and to prove his freedom, is to recover his dignity. (RE, March 1869)

Note: All italics and underline are ours.

Translator’s note:

LE – Book of Spirits     
ESE – Gospel according to Spiritism       
RE – Spiritist Magazine.