Must "first" be followed by "second"?

Question

Is the use of the introductory word *first* awkward or confusing in the following paragraph if I don't include another sentence starting with *secondly*? >In the process of learning them, I deeply felt that there were many more obstacles to overcome for girls than for boys in order to learn technology. First, generally speaking, girls are not as good at logical thinking or as familiar with various softwares as boys are. Another related fact is that professors tend to hire boys as their research assistants, which means that boys are given more opportunities to practice their technologies. I do not use *secondly* to follow the adverb *first*. Do you think this makes my writing less clear? I myself sometimes find the use of "first, second" awkward.

Answer 1

You could start the first sentence “For example…..”  and then keep the second sentence the same.

 

Answer 2

For correct sentence construction, in your example above, you should use firstly instead of first. You should use secondly to follow the sequence or order of information and end with lastly or finally. If you only have 2 points, use firstly and additionally.