The Bible says that Adam was created before Eve. This point is often used by believers, including the biblical authors, to explain why men are in authority over women.

1 Timothy 2:12-13 is an example...
12 I do not permit a woman to teach or to assume authority over a man she must be quiet. 13 For Adam was formed first, then Eve.


I want to know what science says about the matter.

For Discussion - Is there a scientific basis for claiming that males existed before females? What is the evidence? Anything conclusive?
 
Here are some facts to provide context:
Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.
...
Humans are primates. Physical and genetic similarities show that the modern human species, Homo sapiens, has a very close relationship to another group of primate species, the apes. Humans and the great apes (large apes) of Africa -- chimpanzees (including bonobos, or so-called “pygmy chimpanzees”) and gorillas -- share a common ancestor that lived between 8 and 6 million years ago. Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa.
Most scientists currently recognize some 15 to 20 different species of early humans.
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Early humans first migrated out of Africa into Asia probably between 2 million and 1.8 million years ago. They entered Europe somewhat later, between 1.5 million and 1 million years. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60,000 years and to the Americas within the past 30,000 years or so. The beginnings of agriculture and the rise of the first civilizations occurred within the past 12,000 years.
Source: https://humanorigins.si.edu/education/introduction-human-evolution

I'm still looking for a good source to answer the specific questions in the OP. It's not as easy as I thought as there doesn't seem to be any definitive answer. In general, Google Ai search result gave me this response:
In the context of biological evolution, neither male nor female sex came first. Instead, sexual reproduction likely evolved from simpler, asexual forms of reproduction, with the emergence of distinct male and female sexes occurring later. Initially, single-celled organisms engaged in isogamy, where all individuals produced gametes (sex cells) of similar size. Over time, some organisms specialized in producing smaller, more mobile gametes (sperm), while others specialized in producing larger, nutrient-rich gametes (eggs), leading to the evolution of anisogamy and ultimately, separate male and female sexes.
Source: https://www.google.com/search?q=whi...BWY4ChDy0wN6BAgJEAQ&biw=1701&bih=885&dpr=2.25

That's a good starting point.