The question can be remedied without any theology or biblical teaching, it is a natural law.
Gravity is part of the natural law which tells us that if we step off a ten story building, or a one story building, we will fall and most like be terribly hurt or die.
Sexuality is also proven by the natural law.
Here is a man made analogy for the natural law. Take for instance a bolt and a nut that fit together. The two are complimentary in that they fit each other for a purpose. The purpose is to fasten things together. If you tried to fasten the same things together with two bolts or two nuts only, then the object would fall apart. If the complimentary pair are not used in the application, then it does not work to fit the purpose it was given. The same can be said for sexuality.
We know from nature and science that male and female are scientifically and naturally complimentary. It takes one man and one woman to conceive a child, period. Even in a test tube baby, it took the sperm from the male human and the egg from the female human to make the new life we like to call an embryo. It is better said that this is a new human in the embryonic stage of life, just as the tadpole is a frog in the embryonic or tadpole stage of development. There are no exceptions to the fact that it takes one human man and one human woman to make a new human life, always.
Therefore if you take two human males and try to procreate, it is impossible, just as it is for two female humans. There is no exception whatsoever.
Nature and science show that the natural result of sexual relations between one male and one female human, brings forth a new human being. This is never an accident because this is the natural result and everyone knows this who is of the age to be having sexual relations. To want the act and not the result is unnatural and wishful thinking.
There is nothing complimentary about two humans of the same sex having some type of awkward sexual relations outside of the design that is evident in nature. The female uteris opens when climaxing, expanding and reaching downward to receive the semen of the male. This is just one of the dozens of natural reactions which occur during the sexual act, showing that it is meant exclusively for male and female. Two females have no way of procreating so any sexual act between them is purely for personal enjoyment and never for the natural intended purpose at all. It would be purely selfish sexual relations. The same thing with two males. Semen is designed to transport sperm for the purpose of conceiving a new human life and nothing more. Although sexual relations are naturally supposed to be pleasing to each partner, the end result inevitably and normatively is a new human life between one male and one female human being. The same can be said for pretty much all mammals.
You may ask “what about those who cannot conceive a child”? This would be the exception. The fact that we are fallible and not perfect tells us that there will be women and men who cannot procreate. This could be for many reasons. It still goes back to the fact that there can never be procreation without one male human and one female human.
For anyone who is homosexual(not gay), it would take going OUTSIDE of their claimed sexuality to conceive a child, therefore proving that they are not only not truly homosexual, but have desires which heterosexuals have, once again proving that they are not fully homosexual in their desires. Why would anyone who supposedly only has the desires for the same sex, ever want a child which can only be accomplished through heterosexual means? This is the natural desire of heterosexuals and is limited to the heterosexual act of male and female having sexual intercourse, naturally.
Many people have the desire to have sex with non humans and even small children, which are totally not complimentary and unnatural desires. Should we then let these people have sex with animals and children because that is their desire, even though it is not natural, scientifically speaking? Of course not. In the same way, if someone has desired to kill humans from a very young age, as early as they can remember, should we let them kill when they desire and how they desire to fill their wants? Of course not because it goes against the natural law and is not a complimentary act for humans. None of the afore mentioned acts are life giving and therefore are immoral and unnatural, scientifically speaking.
Just because a person has the desire for something, does not mean they need to act on it. Having the desires for the same sex is not a sin. Acting on the desire is sinful and a defect in the character of the human being. Persons with the desire for the same sex can be more fully satisfied through service to God and others. I am an exhomosexual and have experienced both side of this situation. The desire for the same sex was removed over 17 years ago and I am happily marrid and have 3 children and one on the way. i thank God for his mercy and grace. I am a walking miracle. My heart longs forthose who struggle deeply with these desires and they do not go away. My prayers are with them.
I hope this helps. peace RSH