From a biological point of view, such a thing is possible, because the intake of certain foods affects the environment in the vagina, which in turn affects the male sperm "arriving" in the female vagina with the aim fertilization of the egg. For example, the influence of acidic foods leads to overacidification of the vagina, which can lead to the death of spermatozoa that carry the Y chromosome. As a result, the probability of conceiving a boy is reduced.