At conception, an X chromosome and a Y chromosome determine the sex of the offspring, due to genes located on the Y chromosome that code for maleness. Conceptus have two sex chromosomes: a conceptus with two X chromosomes (XX) is female, and a conceptus with an X and a Y chromosome (XY) is male.
Of course, there are exceptions, rare and unfortunate genetic abnormalities, in which there may be a resulting confusion of gender and sexual dysfunction, but in healthy and normal human persons (which is the aim of medical science to identify and promote) it is as clear as 2 + 2 = 4! Every cell of the male body is male and every cell of the female body is female, and the soul, likewise, is male or female because natural gender is constitutive of the personhood of man, male or female.
And God created man to his own image: to the image of God he created him: male and female he created them. (Genesis 1:27)
"Have ye not read, that he who made man from the beginning, Made them male and female?" --Jesus Christ (on why divorce is a sin, Matthew 19:4)
Homosex is one of the various misuses of the sexual faculty which was created in man for true conjugal union and for procreation. It is not homophobia to say so, just a matter of fact. Actually, to deny that is prejudicial towards people who have same sex attraction, because it is an attempt to exclude them from the mass of humanity which has to exercise the virtue of chastity in accord with each person's creative specificity. Creation is specific, and male or female is an essential part of that specificity of creation. Every man is called to live his life accordingly, according to the call of his created order!
Cf. What’s in a Name? Why Christians Should Be Wary of the Word "Transgender", Homosexuality and health
P.S. It is good to consider the truth of the human body and it's relation to the human person as we celebrate the bodily ascension of Jesus Christ, man, male, in the flesh, ascended into heaven 1984 years ago, last Thursday. 2017 we are celebrating the second millennium of the seventeen year old Christ, man, in the flesh, male, on earth. The Creator and Lord of all each and every man, male or female.
P.S. It is good to consider the truth of the human body and it's relation to the human person as we celebrate the bodily ascension of Jesus Christ, man, male, in the flesh, ascended into heaven 1984 years ago, last Thursday. 2017 we are celebrating the second millennium of the seventeen year old Christ, man, in the flesh, male, on earth. The Creator and Lord of all each and every man, male or female.