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I believe that given what I have heard about war and that up until whenever only men fought in wars then to replace the amount dead so that it would be equal on earth then more male births would occur than females. what is your thought?

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  • $\begingroup$ Yes, the ratio is around 1.07:1, for males to females. But this is likely due to far more factors than male mortality rates. Also, it would've been quicker to Google your question than to ask Stackexchange. $\endgroup$ – Jam Sep 10 '18 at 12:25
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    $\begingroup$ Your post is mainly constituted of a single large sentence. This sentence is very hard to understand and is full of grammatical issues (you might be an ESL, like I am myself). That makes it hard to understand your question. Also, please capitalize the first letter of your sentences. $\endgroup$ – Remi.b Sep 10 '18 at 17:46
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Are more males born than females in humans?

According to the CIA (the only reference I could find; see here click on "people and society" and look for "sex ratio"), the world wide sex ratio at birth is 1.03 males for every female. This sex ratio is reversed at old age (women's life expectancy is higher than men's).

at birth: 1.03 male(s)/female

0-14 years: 1.07 male(s)/female

15-24 years: 1.07 male(s)/female

25-54 years: 1.02 male(s)/female

55-64 years: 0.95 male(s)/female

65 years and over: 0.81 male(s)/female

total population: 1.02 male(s)/female (2017 est.)

Note that these statistics somehow ignores the cases of intersex which accounts for a not completely negligible part of the population (see here). In short, yes, more males are born than females.

Why are there more males born than females in humans?

It is unclear from your post whether you are looking for proximal or ultimate causation and your explanation is made unclear by the bad grammar in your post.

Orzack et al. (2015) (thanks @iayork for the reference) investigate the reasons for this unequal sex ratio at birth. From their abstract

Our results indicate that the sex ratio at conception is unbiased, the proportion of males increases during the first trimester, and total female mortality during pregnancy exceeds total male mortality

While I have not read the whole paper, intuitively, I would tend to think that females babies might have a higher miscarriage probability, which cause the observed discrepancy. For example, X chromosome inactivation (dosage compensation) that happen in females only, and the development of female reproductive system (which is arguably more complex than the male's reproductive system) could cause of higher miscarriage probability among females than males. This is all hypothetical though and you should have a look at the link paper.

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    $\begingroup$ I don't know of any study that investigate the reasons for this unequal sex ratio at birth. There are many. A recent review (The human sex ratio from conception to birth) concludes that "total female mortality during pregnancy exceeds total male mortality". $\endgroup$ – iayork Sep 10 '18 at 18:57
  • $\begingroup$ This is a big correction of my post and an important add up (you could have made it a new post). Thanks. I edited my post. $\endgroup$ – Remi.b Sep 10 '18 at 19:03

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